Computing session multi-factor authentication

A computing device includes a memory and a processor configured to cooperate with the memory to receive a connection lease and a token from a client device, with the token being generated responsive to the client device completing multi-factor authentication (MFA) with a provider of MFA. The processor further verifies, responsive to unavailability of the provider of MFA, that the client device has previously performed MFA based upon the token, and connect the client device to a computing session with use of the connection lease and responsive to the verification that the client device has performed MFA.

BACKGROUND

Many organizations are now using applications to provide a more flexible option to address the varying needs of their users. In desktop virtualization, a user's operating system, applications, and/or user settings may be separated from the user's physical smartphone, laptop, or desktop computer. Using client-server technology, a “virtualized desktop” may be stored in and administered by a remote server, rather than in the local storage of a client computing device.

There are several different types of desktop virtualization systems. Virtual Desktop Infrastructure (VDI) refers to the process of running a user desktop inside a virtual machine that resides on a server. Virtualization systems may also be implemented in a cloud computing environment in which a pool of computing desktop virtualization servers, storage disks, networking hardware, and other physical resources may be used to provision virtual desktops, and/or provide access to shared applications.

SUMMARY

A computing device may include a memory and a processor configured to cooperate with the memory to receive a connection lease and a token from a client device, with the token being generated responsive to the client device completing multi-factor authentication (MFA) with a provider of MFA. The processor may further verify, responsive to unavailability of the provider of MFA, that the client device has previously performed MFA based upon the token, and connect the client device to a computing session with use of the connection lease and responsive to the verification that the client device has performed MFA.

In an example embodiment, the connection lease may include data about the MFA, and the processor may be further configured to verify that the token is current based upon the data, and connect the client device to the computing session also responsive to verification of the token being current. In another example embodiment, the processor may verify that the client device has performed MFA for external connections outside of a network.

In an example implementation, the token may have an expiration, and the processor may request MFA authentication from the MFA provider prior to the expiration of the token. Additionally, the processor may be further configured to delay the MFA authentication request responsive to the identity provider being offline and extend the connection to the computing session during the delay, for example. Also, the processor may be further configured to change a level of access associated with the computing session responsive to the identity provider being offline, for example.

In one example embodiment, the MFA may comprise generating a Time-based One-time Password (OTP) based upon a key, and the processor may be further configured to receive the key and verify that the client device has performed MFA based upon the key. In accordance with an example implementation, the processor may verify that the client device has previously performed MFA further based upon secondary information. By way of example, the secondary information may comprise an IP address for a prior successful MFA or a latency associated with communications with the client device.

A related method may include, at a computing device, receiving a connection lease and a token from a client device, with the token being generated responsive to the client device completing multi-factor authentication (MFA) with a provider of MFA. The method may further include verifying, responsive to unavailability of the provider of MFA, that the client device has previously performed MFA based upon the token, and connecting the client device to a computing session with use of the connection lease and responsive to the verification that the client device has performed MFA.

A related non-transitory computer-readable medium may have computer-executable instructions for causing a computing device to perform steps including receiving a connection lease and a token from a client device, with the token being generated responsive to the client device completing multi-factor authentication (MFA) with a provider of MFA. The steps may further include verifying, responsive to unavailability of the provider of MFA, that the client device has previously performed MFA based upon the token, and connecting the client device to a computing session with use of the connection lease and responsive to the verification that the client device has performed MFA.

DETAILED DESCRIPTION

One approach for providing resiliency to users connecting to remote computing sessions are Connection Leases (CLs), which provide long-lived mostly static entitlements to published resources. Another approach is Progressive Web App (PWA) Service Worker caching, which allows for web-based user interface (UI) to be functional even in offline or degraded network conditions. Some entities require Multi-factor Authentication (MFA) to be performed regularly (e.g., hourly) by its users. However, CLs are typically valid for a longer period (e.g., a week) by default. CLs are user-device bound long-lived tokens. In particular, CLs may be signed, encrypted to the user endpoint device, and include an endpoint public key thumbprint for anti-theft protection.

Notwithstanding the security of CLs, certain entities may still require MFA within a CL architecture. Yet, this may result in problems when attempting to strictly apply MFA within a shorter period of time during offline and cloud outage conditions. That is, while CLs are designed to be used during such offline conditions, MFA cloud services are usable when an Internet connection is available and other identity provider cloud services are also available and healthy. The systems and methods described herein overcome these technical challenges by using a token to verify, during an offline condition, that a client device has previously completed MFA. That is, the token is generated responsive to the client device completing MFA with a provider of MFA (e.g., MFA cloud services), and the token may be cached at a computing device for use during an offline condition so that the computing device may still connect the client device to a requested computing session using the token and in compliance with MFA policy.

Referring initially toFIG.1, a non-limiting network environment10in which various aspects of the disclosure may be implemented includes one or more client machines12A-12N, one or more remote machines16A-16N, one or more networks14,14′, and one or more appliances18installed within the computing environment10. The client machines12A-12N communicate with the remote machines16A-16N via the networks14,14′.

In some embodiments, the client machines12A-12N communicate with the remote machines16A-16N via an intermediary appliance18. The illustrated appliance18is positioned between the networks14,14′ and may also be referred to as a network interface or gateway. In some embodiments, the appliance108may operate as an application delivery controller (ADC) to provide clients with access to business applications and other data deployed in a data center, the cloud, or delivered as Software as a Service (SaaS) across a range of client devices, and/or provide other functionality such as load balancing, etc. In some embodiments, multiple appliances18may be used, and the appliance(s)18may be deployed as part of the network14and/or14′.

The client machines12A-12N may be generally referred to as client machines12, local machines12, clients12, client nodes12, client computers12, client devices12, computing devices12, endpoints12, or endpoint nodes12. The remote machines16A-16N may be generally referred to as servers16or a server farm16. In some embodiments, a client device12may have the capacity to function as both a client node seeking access to resources provided by a server16and as a server16providing access to hosted resources for other client devices12A-12N. The networks14,14′ may be generally referred to as a network14. The networks14may be configured in any combination of wired and wireless networks.

In some embodiments, a server16may execute a remote presentation services program or other program that uses a thin-client or a remote-display protocol to capture display output generated by an application executing on a server16and transmit the application display output to a client device12.

In yet other embodiments, a server16may execute a virtual machine providing, to a user of a client device12, access to a computing environment. The client device12may be a virtual machine. The virtual machine may be managed by, for example, a hypervisor, a virtual machine manager (VMM), or any other hardware virtualization technique within the server16.

In some embodiments, the network14may be: a local-area network (LAN); a metropolitan area network (MAN); a wide area network (WAN); a primary public network14; and a primary private network14. Additional embodiments may include a network14of mobile telephone networks that use various protocols to communicate among mobile devices. For short range communications within a wireless local-area network (WLAN), the protocols may include 802.11, Bluetooth, and Near Field Communication (NFC).

FIG.2depicts a block diagram of a computing device20useful for practicing an embodiment of client devices12, appliances18and/or servers16. The computing device20includes one or more processors22, volatile memory24(e.g., random access memory (RAM)), non-volatile memory30, user interface (UI)38, one or more communications interfaces26, and a communications bus48.

The user interface38may include a graphical user interface (GUI)40(e.g., a touchscreen, a display, etc.) and one or more input/output (I/O) devices42(e.g., a mouse, a keyboard, a microphone, one or more speakers, one or more cameras, one or more biometric scanners, one or more environmental sensors, and one or more accelerometers, etc.).

The non-volatile memory30stores an operating system32, one or more applications34, and data36such that, for example, computer instructions of the operating system32and/or the applications34are executed by processor(s)22out of the volatile memory24. In some embodiments, the volatile memory24may include one or more types of RAM and/or a cache memory that may offer a faster response time than a main memory. Data may be entered using an input device of the GUI40or received from the I/O device(s)42. Various elements of the computer20may communicate via the communications bus48.

The illustrated computing device20is shown merely as an example client device or server, and may be implemented by any computing or processing environment with any type of machine or set of machines that may have suitable hardware and/or software capable of operating as described herein.

The processor22may be analog, digital or mixed-signal. In some embodiments, the processor22may be one or more physical processors, or one or more virtual (e.g., remotely located or cloud) processors. A processor including multiple processor cores and/or multiple processors may provide functionality for parallel, simultaneous execution of instructions or for parallel, simultaneous execution of one instruction on more than one piece of data.

The communications interfaces26may include one or more interfaces to enable the computing device20to access a computer network such as a Local Area Network (LAN), a Wide Area Network (WAN), a Personal Area Network (PAN), or the Internet through a variety of wired and/or wireless connections, including cellular connections.

In described embodiments, the computing device20may execute an application on behalf of a user of a client device. For example, the computing device20may execute one or more virtual machines managed by a hypervisor. Each virtual machine may provide an execution session within which applications execute on behalf of a user or a client device, such as a hosted desktop session. The computing device20may also execute a terminal services session to provide a hosted desktop environment. The computing device20may provide access to a remote computing environment including one or more applications, one or more desktop applications, and one or more desktop sessions in which one or more applications may execute.

An example virtualization server16may be implemented using Citrix Hypervisor provided by Citrix Systems, Inc., of Fort Lauderdale, Florida (“Citrix Systems”). Virtual app and desktop sessions may further be provided by Citrix Virtual Apps and Desktops (CVAD), also from Citrix Systems. Citrix Virtual Apps and Desktops is an application virtualization solution that enhances productivity with universal access to virtual sessions including virtual app, desktop, and data sessions from any device, plus the option to implement a scalable VDI solution. Virtual sessions may further include Software as a Service (SaaS) and Desktop as a Service (DaaS) sessions, for example.

Referring toFIG.3, a cloud computing environment50is depicted, which may also be referred to as a cloud environment, cloud computing or cloud network. The cloud computing environment50can provide the delivery of shared computing services and/or resources to multiple users or tenants. For example, the shared resources and services can include, but are not limited to, networks, network bandwidth, servers, processing, memory, storage, applications, virtual machines, databases, software, hardware, analytics, and intelligence.

In the cloud computing environment50, one or more clients52A-52C (such as those described above) are in communication with a cloud network54. The cloud network54may include backend platforms, e.g., servers, storage, server farms or data centers. The users or clients52A-52C can correspond to a single organization/tenant or multiple organizations/tenants. More particularly, in one example implementation the cloud computing environment50may provide a private cloud serving a single organization (e.g., enterprise cloud). In another example, the cloud computing environment50may provide a community or public cloud serving multiple organizations/tenants. In still further embodiments, the cloud computing environment50may provide a hybrid cloud that is a combination of a public cloud and a private cloud. Public clouds may include public servers that are maintained by third parties to the clients52A-52C or the enterprise/tenant. The servers may be located off-site in remote geographical locations or otherwise.

The cloud computing environment50can provide resource pooling to serve multiple users via clients52A-52C through a multi-tenant environment or multi-tenant model with different physical and virtual resources dynamically assigned and reassigned responsive to different demands within the respective environment. The multi-tenant environment can include a system or architecture that can provide a single instance of software, an application or a software application to serve multiple users. In some embodiments, the cloud computing environment50can provide on-demand self-service to unilaterally provision computing capabilities (e.g., server time, network storage) across a network for multiple clients52A-52C. The cloud computing environment50can provide an elasticity to dynamically scale out or scale in responsive to different demands from one or more clients52. In some embodiments, the computing environment50can include or provide monitoring services to monitor, control and/or generate reports corresponding to the provided shared services and resources.

In some embodiments, the cloud computing environment50may provide cloud-based delivery of different types of cloud computing services, such as Software as a service (SaaS)56, Platform as a Service (PaaS)58, Infrastructure as a Service (IaaS)60, and Desktop as a Service (DaaS)62, for example. IaaS may refer to a user renting the use of infrastructure resources that are needed during a specified time period. IaaS providers may offer storage, networking, servers or virtualization resources from large pools, allowing the users to quickly scale up by accessing more resources as needed. Examples of IaaS include AMAZON WEB SERVICES provided by Amazon.com, Inc., of Seattle, Washington, RACKSPACE CLOUD provided by Rackspace US, Inc., of San Antonio, Texas, Google Compute Engine provided by Google Inc. of Mountain View, California, or RIGHTSCALE provided by RightScale, Inc., of Santa Barbara, California.

PaaS providers may offer functionality provided by IaaS, including, e.g., storage, networking, servers or virtualization, as well as additional resources such as, e.g., the operating system, middleware, or runtime resources. Examples of PaaS include WINDOWS AZURE provided by Microsoft Corporation of Redmond, Washington, Google App Engine provided by Google Inc., and HEROKU provided by Heroku, Inc. of San Francisco, California.

SaaS providers may offer the resources that PaaS provides, including storage, networking, servers, virtualization, operating system, middleware, or runtime resources. In some embodiments, SaaS providers may offer additional resources including, e.g., data and application resources. Examples of SaaS include GOOGLE APPS provided by Google Inc., SALESFORCE provided by Salesforce.com Inc. of San Francisco, California, or OFFICE 365 provided by Microsoft Corporation. Examples of SaaS may also include data storage providers, e.g. DROPBOX provided by Dropbox, Inc. of San Francisco, California, Microsoft SKYDRIVE provided by Microsoft Corporation, Google Drive provided by Google Inc., or Apple ICLOUD provided by Apple Inc. of Cupertino, California.

Similar to SaaS, DaaS (which is also known as hosted desktop services) is a form of virtual desktop infrastructure (VDI) in which virtual desktop sessions are typically delivered as a cloud service along with the apps used on the virtual desktop. Citrix Cloud is one example of a DaaS delivery platform. DaaS delivery platforms may be hosted on a public cloud computing infrastructure such as AZURE CLOUD from Microsoft Corporation of Redmond, Washington (herein “Azure”), or AMAZON WEB SERVICES provided by Amazon.com, Inc., of Seattle, Washington (herein “AWS”), for example. In the case of Citrix Cloud, Citrix Workspace app may be used as a single-entry point for bringing apps, files and desktops together (whether on-premises or in the cloud) to deliver a unified experience.

The unified experience provided by the Citrix Workspace app will now be discussed in greater detail with reference toFIG.4. The Citrix Workspace app will be generally referred to herein as the workspace app70. The workspace app70is how a user gets access to their workspace resources, one category of which is applications. These applications can be SaaS apps, web apps or virtual apps. The workspace app70also gives users access to their desktops, which may be a local desktop or a virtual desktop. Further, the workspace app70gives users access to their files and data, which may be stored in numerous repositories. The files and data may be hosted on Citrix ShareFile, hosted on an on-premises network file server, or hosted in some other cloud storage provider, such as Microsoft OneDrive or Google Drive Box, for example.

To provide a unified experience, all of the resources a user requires may be located and accessible from the workspace app70. The workspace app70is provided in different versions. One version of the workspace app70is an installed application for desktops72, which may be based on Windows, Mac or Linux platforms. A second version of the workspace app70is an installed application for mobile devices74, which may be based on iOS or Android platforms. A third version of the workspace app70uses a hypertext markup language (HTML) browser to provide a user access to their workspace environment. The web version of the workspace app70is used when a user does not want to install the workspace app or does not have the rights to install the workspace app, such as when operating a public kiosk76.

Each of these different versions of the workspace app70may advantageously provide the same user experience. This advantageously allows a user to move from client device72to client device74to client device76in different platforms and still receive the same user experience for their workspace. The client devices72,74and76are referred to as endpoints.

As noted above, the workspace app70supports Windows, Mac, Linux, iOS, and Android platforms as well as platforms with an HTML browser (HTML5). The workspace app70incorporates multiple engines80-90allowing users access to numerous types of app and data resources. Each engine80-90optimizes the user experience for a particular resource. Each engine80-90also provides an organization or enterprise with insights into user activities and potential security threats.

An embedded browser engine80keeps SaaS and web apps contained within the workspace app70instead of launching them on a locally installed and unmanaged browser. With the embedded browser, the workspace app70is able to intercept user-selected hyperlinks in SaaS and web apps and request a risk analysis before approving, denying, or isolating access.

A high definition experience (HDX) engine82establishes connections to virtual browsers, virtual apps and desktop sessions running on either Windows or Linux operating systems. With the HDX engine82, Windows and Linux resources run remotely, while the display remains local, on the endpoint. To provide the best possible user experience, the HDX engine82utilizes different virtual channels to adapt to changing network conditions and application requirements. To overcome high-latency or high-packet loss networks, the HDX engine82automatically implements optimized transport protocols and greater compression algorithms. Each algorithm is optimized for a certain type of display, such as video, images, or text. The HDX engine82identifies these types of resources in an application and applies the most appropriate algorithm to that section of the screen.

For many users, a workspace centers on data. A content collaboration engine84allows users to integrate all data into the workspace, whether that data lives on-premises or in the cloud. The content collaboration engine84allows administrators and users to create a set of connectors to corporate and user-specific data storage locations. This can include OneDrive, Dropbox, and on-premises network file shares, for example. Users can maintain files in multiple repositories and allow the workspace app70to consolidate them into a single, personalized library.

A networking engine86identifies whether or not an endpoint or an app on the endpoint requires network connectivity to a secured backend resource. The networking engine86can automatically establish a full VPN tunnel for the entire endpoint device, or it can create an app-specific p-VPN connection. A p-VPN defines what backend resources an application and an endpoint device can access, thus protecting the backend infrastructure. In many instances, certain user activities benefit from unique network-based optimizations. If the user requests a file copy, the workspace app70can automatically utilize multiple network connections simultaneously to complete the activity faster. If the user initiates a VoIP call, the workspace app70improves its quality by duplicating the call across multiple network connections. The networking engine86uses only the packets that arrive first.

An analytics engine88reports on the user's device, location and behavior, where cloud-based services identify any potential anomalies that might be the result of a stolen device, a hacked identity or a user who is preparing to leave the company. The information gathered by the analytics engine88protects company assets by automatically implementing counter-measures.

A management engine90keeps the workspace app70current. This not only provides users with the latest capabilities, but also includes extra security enhancements. The workspace app70includes an auto-update service that routinely checks and automatically deploys updates based on customizable policies.

Referring now toFIG.5, a workspace network environment100providing a unified experience to a user based on the workspace app70will be discussed. The desktop, mobile and web versions of the workspace app70all communicate with the workspace experience service102running within the Cloud104. The workspace experience service102then pulls in all the different resource feeds16via a resource feed micro-service108. That is, all the different resources from other services running in the Cloud104are pulled in by the resource feed micro-service108. The different services may include a virtual apps and desktop service110, a secure browser service112, an endpoint management service114, a content collaboration service116, and an access control service118. Any service that an organization or enterprise subscribes to are automatically pulled into the workspace experience service102and delivered to the user's workspace app70.

In addition to cloud feeds120, the resource feed micro-service108can pull in on-premises feeds122. A cloud connector124is used to provide virtual apps and desktop deployments that are running in an on-premises data center. Desktop virtualization may be provided by Citrix virtual apps and desktops126, Microsoft RDS128or VMware Horizon130, for example. In addition to cloud feeds120and on-premises feeds122, device feeds132from Internet of Thing (IoT) devices134, for example, may be pulled in by the resource feed micro-service108. Site aggregation is used to tie the different resources into the user's overall workspace experience.

The cloud feeds120, on-premises feeds122and device feeds132each provides the user's workspace experience with a different and unique type of application. The workspace experience can support local apps, SaaS apps, virtual apps, and desktops browser apps, as well as storage apps. As the feeds continue to increase and expand, the workspace experience is able to include additional resources in the user's overall workspace. This means a user will be able to get to every single application that they need access to.

Still referring to the workspace network environment20, a series of events will be described on how a unified experience is provided to a user. The unified experience starts with the user using the workspace app70to connect to the workspace experience service102running within the Cloud104, and presenting their identity (event 1). The identity includes a user name and password, for example.

The workspace experience service102forwards the user's identity to an identity micro-service140within the Cloud104(event 2). The identity micro-service140authenticates the user to the correct identity provider142(event 3) based on the organization's workspace configuration. Authentication may be based on an on-premises active directory144that requires the deployment of a cloud connector146. Authentication may also be based on Azure Active Directory148or even a third party identity provider150, such as Citrix ADC or Okta, for example.

Once authorized, the workspace experience service102requests a list of authorized resources (event 4) from the resource feed micro-service108. For each configured resource feed106, the resource feed micro-service108requests an identity token (event 5) from the single-sign micro-service152.

The resource feed specific identity token is passed to each resource's point of authentication (event 6). On-premises resources122are contacted through the Cloud Connector124. Each resource feed106replies with a list of resources authorized for the respective identity (event 7).

The resource feed micro-service108aggregates all items from the different resource feeds106and forwards (event 8) to the workspace experience service102. The user selects a resource from the workspace experience service102(event 9).

The workspace experience service102forwards the request to the resource feed micro-service108(event 10). The resource feed micro-service108requests an identity token from the single sign-on micro-service152(event 11). The user's identity token is sent to the workspace experience service102(event 12) where a launch ticket is generated and sent to the user.

The user initiates a secure session to a gateway service160and presents the launch ticket (event 13). The gateway service160initiates a secure session to the appropriate resource feed106and presents the identity token to seamlessly authenticate the user (event 14). Once the session initializes, the user is able to utilize the resource (event 15). Having an entire workspace delivered through a single access point or application advantageously improves productivity and streamlines common workflows for the user.

Turning now toFIG.6, a computing system200illustratively includes a computing device201including a memory202and a processor203configured to cooperate with the memory to receive a connection lease and a token from a client (endpoint) device204. The token is generated responsive to the client device204completing multi-factor authentication (MFA) with a provider of MFA205. The processor203further verifies, responsive to unavailability of the provider of MFA205, that the client device204has previously performed MFA based upon the token, and connects the client device to a computing session206with use of the connection lease and responsive to the verification that the client device has performed MFA.

An example architecture in which the system200may be implemented is now described with reference to a computing system250ofFIG.7. More particularly, the computing system250provides access to virtual sessions based upon connection leases. In the illustrated example, the connection lease generation functions are performed within a cloud computing service255(e.g., Citrix Cloud) which illustratively includes a cloud interface256configured to interface with a client device252for enrollment and lease generation to access virtual sessions254. In an example embodiment, the cloud interface256may be implemented with Citrix Workspace (CWA), and the client device252may be running Citrix Workspace App, although other suitable platforms may be used in different embodiments. The cloud computing service255further illustratively includes a Root of Trust (RoT)257, Connection Lease Issuing Service (CLIS)258, gateway service259, broker260, and database261, which will be described further below.

The client device252has a public-private encryption key pair associated therewith, which in the illustrated example is created by a hardware-backed key store262. The hardware-backed key store262prevents the client device252operating system (OS) from accessing the private key. The client device252OS performs cryptographic operations with the private key, but without the ability to access/export the key. Examples of hardware-backed key stores include Trusted Platform Module (TPM) on a personal computer (PC), iOS Secure Enclave, and Android Hardware Key Store, for example, although other suitable encryption key generation platforms may also be used. By way of background, in some embodiments, a hardware-backed key store262, such as a TPM, is a microchip installed on the motherboard of client device252and designed to provide basic security-related functions, e.g., primarily involving encryption keys. A hardware-backed key store262communicates with the remainder of the system by using a hardware bus. A client device252that incorporates a hardware-backed key store262can create cryptographic keys and encrypt them so that they can only be decrypted by the hardware-backed key store262. This process, referred to as wrapping or binding a key, can help protect the key from disclosure, such as from other parts of the client device252(e.g., the client device operating system (OS) as described above), and therefore from potential exfiltration to malicious processes running on the client device or from exfiltration to other devices. A hardware-backed key store262could have a master wrapping key, called the storage root key, which is stored within the hardware-backed key store262itself. The private portion of a storage root key or endorsement key that is created in a hardware-backed key store262is never exposed to any other component, software, process, or user. Because a hardware-backed key store262uses its own internal firmware and logic circuits to process instructions, it does not rely on the operating system, and it is not exposed to vulnerabilities that might exist in the operating system or application software.

Turning back toFIG.7, the client device252provides its public key to the cloud interface256(step (1) inFIG.7), which then has the public key signed by the RoT257(step (2) inFIG.7) and returns the signed public key to the client device (step (3) inFIG.7). Having the public key signed by the RoT257is significant because the gateway263, the virtual delivery appliance253, and the broker260also trust the RoT and can therefore use its signature to authenticate the client device public key.

The client device252may then communicate with the CLIS258via the cloud interface256to obtain the connection lease (step (4) inFIG.7). The client device252public key may be provided to a host or virtual delivery appliance253(e.g., Citrix VDA) either indirectly via the broker260or directly by the client device. In the present example, the virtual delivery appliance253is enabled for use with connection leases, in contrast to the legacy virtual delivery appliance204described above. If the client device252public key is indirectly provided to the virtual delivery appliance253, then the security associated with the client-to-broker communications and virtual delivery appliance-to-broker communications may be leveraged for secure client public key transmission. However, this may involve a relatively large number of client public keys (from multiple different client devices252) being communicated indirectly to the virtual delivery appliance253.

On the other hand, the client device252public key could be directly provided by the client device to the virtual delivery appliance253, which in the present case is done via the gateway263(step (5) inFIG.7). Both the client device252and the virtual delivery appliance253trust the RoT257. Since the virtual delivery appliance253trusts the RoT257and has access to the RoT public key, the virtual delivery appliance253is able to verify the validity of the client device252based on the RoT signature on the public key and, if valid, may then trust the client device public key. In yet another embodiment, the client device public key may also optionally be signed by the broker260beforehand. Both the client device252and the virtual delivery appliance253trust the broker260. Since the virtual delivery appliance253trusts the broker260and has access to the broker public key, the virtual delivery appliance253is able to verify the validity of the client device252based on the broker signature on the public key and, if valid, may then trust the client device public key. In the illustrated example, the signed public key of the client device252is provided directly to the virtual delivery appliance253along with the connection lease via a gateway263. In an example implementation, the gateway263may be implemented using Citrix Gateway, for example, although other suitable platforms may also be used in different embodiments.

The virtual delivery appliance253and gateway263may communicate with the broker260and gateway service259(which may be implemented using Citrix Secure Web Gateway, for example) via a cloud connector264. In an example embodiment, the cloud connector264may be implemented with Citrix Cloud Connector, although other suitable platforms may also be used in different embodiments. Citrix Cloud Connector is a component that serves as a channel for communication between Citrix Cloud and customer resource locations, enabling cloud management without requiring complex networking or infrastructure configuration. However, other suitable cloud connection infrastructure may also be used in different embodiments.

The client device252signed public key or a hash of the client device signed public key (thumbprint) is included in the connection lease generated by the CLIS258and is one of the fields of the connection lease that are included when computing the signature of the connection lease. The signature of the connection lease helps ensure that the connection lease contents are valid and have not been tampered with. As a result, a connection lease is created for the specific client device252, not just a specific authenticated user.

Furthermore, the virtual delivery appliance253may use a challenge-response to validate that the client device252is the true owner of the corresponding private key. First, the virtual delivery appliance253validates that the client device252public key is valid, and more particularly signed by the RoT257and/or broker260(step (6) inFIG.7). In the illustrated example, the client device252public key was sent directly by the client device to the virtual delivery appliance253, as noted above. In some embodiments, connection lease revocation may be applied when a client device252or virtual delivery appliance253is offline with respect to the CLIS258or broker260. Being online is not a requirement for use of a connection lease since connection leases may be used in an offline mode. Connection lease and revocation list details may be stored in the database261for comparison by the broker260with the information provided by the virtual delivery appliance253.

Second, upon early session establishment, e.g. after transport and presentation-level protocol establishment, between the client device252and virtual delivery appliance253, the virtual delivery appliance253challenges the client device252to sign a nonce (an arbitrary number used once in a cryptographic communication) with its private key (step (7) inFIG.7). The virtual delivery appliance253verifies the signature of the nonce with the client device252public key. This allows the virtual delivery appliance253to know that the client device252is in fact the owner of the corresponding private key. It should be noted that this step could be performed prior to validating the public key of the client device252with the RoT257and/or broker260in some embodiments, if desired.

Furthermore, the virtual delivery appliance253validates that the connection lease includes the public key (or hash of public key) matching the client device252public key. More particularly, the virtual delivery appliance253first validates the connection lease signature and date, making sure that the broker260signature on the lease is valid (using the RoT257signed broker public key, since the virtual delivery appliance trusts the RoT) and that the lease has not expired. Moreover, the virtual delivery appliance253may verify that the connection lease includes the client device252public key, or a hash of the client device public key, in which case the virtual delivery appliance computes the hash of the client device public key. If the connection lease includes the matching client device252public key, then the virtual delivery appliance253confirms that the connection lease was sent from the client device for which it was created.

As a result, if a connection lease is stolen from the client device252and used from a malicious client device, the session establishment between the malicious client and the virtual delivery appliance253will not succeed because the malicious client device will not have access to the client private key, this key being non-exportable and stored in the hardware-backed key store262.

The illustrated connection lease management infrastructure also advantageously allows for connection lease validation using a “reverse prepare for session” operation from the virtual delivery appliance253(e.g., a Citrix VDA, etc.), as a target resource location, to the Broker260(e.g., Citrix Virtual Apps and Desktops Broker). This may be done in conjunction with the connection lease exchange that occurs between the client device252and the virtual delivery appliance253, and utilizing signed responses from the broker260and virtual delivery appliance253. These play a significant role for the resiliency, security, performance and user experience (UX) with respect to connection leasing. However, because the legacy virtual delivery appliances204described above with reference toFIG.6are not configured for such connection lease exchanges, these advantages would not otherwise be possible while using such legacy appliances.

Connection leases (CLs) provide long-lived, mostly static entitlements to published resources. Furthermore, Progressive Web App (PWA) Service Worker caching, which may also be used within the above-described architecture, allows for Web-based user interface (UI) (e.g., the Workspace UI) to be functional even in offline or degraded network conditions. In an example implementation, the system250will support native CWA apps. However, a significant amount of users may utilize a browser for the Workspace/StoreFront store256, but also have a native CWA instance installed on the endpoint device252, so that following the launch within the browser (Workspace Store) window, the native HDX Engine is invoked with the downloaded ICA (connection descriptor) file. This use case may be considered a “hybrid” case. This approach helps ensure familiar user experience (UX) with the browser and at the same time better HDX performance (e.g., for graphics, multimedia) and feature set (e.g. Smart Card, USB, Seamless Windows) compared to using an HTML5 HDX Engine in the browser.

There are also some use cases where no native CWA components are installed on the endpoint device252. This is a zero-install configuration where both the Workspace Store256and the HDX Engine (HTML5-based) reside within the browser. This use case may be considered a “pure” browser case.

In both of these cases, the user authentication context is in the browser, and using a browser has unique challenges. For example, the browser does not offer the same level of security for asset storage as a native CWA instance, such as: access to the TPM, storage of private/public key pairs, signed public keys, Connection Leases (CL), Gateway Connection Tickets (GCT), Long Lived Auth Tokens (LLAuthT), Polymorphic Auth Tokens (PAuthT) for single sign on (SSOn) into HDX, etc. Another challenge is that the browser does not offer the same level of persistence, e.g., the browser could be configured to clear the cache upon exit, including device reboot.

Furthermore, the browser has a limited lifetime, in that it can be closed by a user after a brief use. This diminishes the opportunity for background operations that are important for resiliency, e.g., periodic download of CLs, which may otherwise be performed by a native app. Browsers may also have a significant attack surface, and access to native (raw) sockets is generally limited. More particularly, Web browsers have a significant attack surface by design, since they are used to access external websites (typically not under the control of an organization). This is why most modern browsers generally implement a sandbox to limit access to the operating system native APIs (including native sockets). As a consequence, it makes it difficult to access the native OS APIs which we need for the hybrid case described above (i.e., to communicate the native CWA components) or the zero-install case noted above (for which the HDX Engine is HTML5-based). In the zero-install case, the HTML5-based HDX Engine (the CWA is entirely running in the browser context) needs to communicate over the CLXMTP protocol with other components like the Gateway263or the Connector264/VDA253. CLXMTP typically runs directly over TCP (or UDP) transport protocols and this requires to use native sockets which might not be accessible (depending on the browser sandbox). The HTML5-based HDX Engine may use WebSockets to communicate with other components (there is no restriction for CLXMTP to use WebSockets as its transport protocol), but this would require the other components (e.g. Gateway263, Connector264/VDA253) to also implement/use the WebSockets protocol (i.e. open a listener for WebSocket connections, accept WebSocket connections, etc.f). Although WebSockets can be used to channel protocols such as secure connection lease protocols (which will be discussed further below), this requires adding WebSocket support to multiple backend systems such as Gateway263, Connector264, and VDA253, which bears a higher engineering cost.

In addition, with the browser there is no “user” awareness, which makes kiosk support for usage by multiple users on a shared kiosk device or terminal difficult and potentially unfeasible. By design, current Web browsers (Chrome, Edge, etc.) run in the context of a user's session on the underlying OS. For instance, if a user logs on to Windows and launches a Chrome instance, the Chrome instance runs in the context of the user's logged on session. If the user's session is logged on for a shared account to be used in the context of a kiosk, the browser does not provide much functionality to distinguish between the users of the kiosk. For example, each user of the kiosk can authenticate to the HTML5 CWA (i.e., logging on to Citrix Workspace after walking to a kiosk, but not logging on to Windows because the shared account is already logged on). The HTML5 CWA could use HTML5 Web Storage to store data. However, HTML5 Web Storage has no concept of user differentiation, meaning that the available storage would have to be explicitly subdivided per kiosk user. This could be challenging to do, especially from a security point of view. Furthermore, security, resiliency and performance of components such as UI caching, keys, CLs and various other user-device-bound tokens is important to maintain to prevent unauthorized access to the system. Moreover, it may also be desirable to enable multi-user, multi-store and kiosk (shared terminal) use cases.

Turning toFIG.8, an example implementation of the system200which is implemented using the connection lease infrastructure set forth inFIG.7is now described. The following is a table of abbreviations which will be used in the description of the system200.

AbbreviationMeaningIPIdentity Platform which may provide its ownIdentity Provider (IDP) but can also integratewith third party IDPs or other identity systems.CLConnection LeaseCLISConnection Lease Issuing ServiceCLXMTPConnection Lease Exchange and Mutual TrustProtocolWAWorkspace AppDSAuthTDS Authentication Token (primary unlessotherwise specified as secondary for specificservice)DS AuthDelivery Services AuthFIDO2Fast Identity Online 2IDPIdentity ProviderOIDCOpenID ConnectMFAMulti-factor AuthenticationRPRelying PartySSOnSingle Sign OnTOTPTime-based One-time PasswordWSWorkspaceWSPWorkspace PlatformCLSConnection Lease Service

In the illustrated example, the endpoint device204runs a native WA instance208. The native WA instance208illustratively includes a common connection manager (CCM)286and a high definition (HD) connection engine287for communicating with a gateway263, connector264, and/or VDA253to access virtual resources (e.g., virtual apps/desktops, SaaS/DaaS servers, etc.), as discussed further above. A Self-Service Plugin (SSP)288may perform calls home to the IP/IDP265and CLIS258on behalf of the WA instance208. The endpoint device204further illustratively includes a PWA and in-app caching module282which interfaces with Workspace256and provides multi-feed resource awareness as well as a resource cache276for dynamic assets including published assets (such as virtual apps and desktops). The WA instance208further illustratively includes an MFA Token (MFAT) store276, as well as key store279afor the public/private key pair of the endpoint device204. A cache289provides a key store279bfor signed public keys of other components (e.g., VDA253, Gateway263), and CL storage, for the HD engine287and CL synch engine285.

In the present example, the MFA Token (MFAT) serves as evidence of recent successful MFA by the endpoint device204. The MFAT may take the form of a signed JSON object similar to a CL or Gateway Connection Ticket (GCT). In addition to JSON as the data format for CLs and GCTs, other options may include binary (e.g. ASN.1 with BER), XML or any format for structured data. The MFAT must to be signed or it would not be trustable. The MFAT is user-device bound, and may include a user identity and endpoint public key thumbprint, similar to a CL or GCT. In the present example, MFATs may be issued by IP/IDP265following MFA and signed by an IP private key. An IP/IDP265public key signed by the RoT257may also be included with the MFAT, for example. In an example embodiment, an MFA expiration time is set (e.g., 60 minutes) plus an optional grace period (e.g., 30 minutes), although different times may be used in different embodiments.

In some embodiments, an optional payload may also be included, e.g., with additional policies (not encrypted), or user TOTP secret key (encrypted), as will be discussed further below. The MFAT may be retrieved synchronously with the MFA flow, as opposed to a background CL plus keys sync. Resource CLs may optionally include an MFA policy requirement, that is, indicating that an MFAT is required along with the resource CL. This helps avoid the need to push MFA policies to the gateway263, connector264, VDA253, or other components (any of which may serve as the computing device201shown inFIG.6). Instead, the policy is included in the CL. However, it should be noted that in some embodiments, MFA policies may in addition or instead be pushed to the gateway263, connector264, and/or VDA253to provide the ability to change MFA policies in real time. Otherwise, CL policies would be more static because CLs are typically issued for 1-30 days.

The CLIS258may read MFA policies to include in resource CLs it generates. The gateway263, connector264, and/or VDA253enforce MFA tokens based on instructions in the resource CL. MFAT signatures are validated based upon the IP/IDP265public key included in the signature which is signed by the RoT257, and then validated with the included public key. The expiration of the MFAT may then be checked to ensure that MFA has been recently performed by the endpoint device204. Furthermore, a check may also be performed to ensure that the user-device identity in the MFAT matches that of resource CL, and also matches the public key used in a trusted CL exchange protocol.

Using the above-noted example, the duration of outages may range from [grace period (30 min)] as a minimum to [MFA time (60 min)+grace period (30 min)] as a maximum. In other words, in the worst-case scenario, MFA was performed, and approximately 59 minutes later right before the next MFA challenge an outage occurs. Then the MFA token is valid for another approximately 31 minutes.

Various enhancements may be used in different implementations. One enhancement is to enforce MFA for external access only. More particularly, a policy in the CL may dictate that the MFA token requirement is applied for external connections, but not for direct connections internal to a computing environment or network. By way of example, this may be enforced at the Gateway263and optionally at the Connector264. This means that resiliency of direct connections is not impacted at all, e.g., the service level agreement (SLA) could be 0.9999 for direct connections and 0.995 for external connections plus MFA (although other metrics may be used in different embodiments).

In accordance with another implementation, the availability of a Gateway Service259connection implies that there are no issues with the user's Internet. So, this allows for a focus on IP/IDP265health-checks. Furthermore, since the endpoint device204is typically not to be trusted, the Gateway263may perform the IP/IDP265health checks instead. According to an example CL policy, if the IP/IDP265is down, the grace period encoded in the MFAT may then be used, e.g. 30 minutes. Otherwise, if the IP/IDP265is up, the grace period is not allowed. In an alternative arrangement, the grace period encoded in the MFAT may always be allowed, but if the IP/IDP265is down, then allowance may be provided for an extended grace period, e.g., 60 minutes (although other durations may also be used). In yet another option for CL policy, unlimited grace period usage may be allowed so long as the IP/IDP265is down.

Another optional enhancement is deferred MFA policy application. That is, a connection may be allowed to proceed and the user allowed to log into a session, but then a deferred MFA policy is applied. The deferred MFA policy may be applied after a grace period (e.g., an additional 15 minutes), or when the IP/IDP265is known to be healthy again, whichever comes first. If after the grace period expires the IP/IDP265is still down, the user may be warned that the connection will be dropped, and then Gateway263drops the HD connection. If the IP/IDP265becomes healthy before the grace period expires, the Gateway263sends an MFA authentication request to the WA instance208. The WA instance208attempts MFA authentication and, if successful, obtains a new MFAT. The WA instance208provides the new MFAT to the Gateway263. This may be done by re-running CLXMTP over an HD connection with the CLs and the new MFAT. Alternatively, the MFAT may be sent via a Common Gateway Protocol (CGP) and validated at the Gateway263based on the stored endpoint thumbprint and CL policies from a gateway connection ticket (GCT). After CL and MFAT validation, the HD connection is allowed to continue. The policy may optionally have additional details, e.g., if connecting from the same client IP, allow the connection for a longer grace period.

It should be noted that the approaches discussed herein will also work with CLs being the preferred code path, that is, they may be also be used in online conditions in that they provide for improved security through MFA verification in outage conditions in addition to resiliency. In some implementations (e.g., on-premises), some organizations use MFA for direct/internal connections in addition to external connection. In such cases, the Connector264and/or VDA253may perform the equivalent of the IP/IDP265health checks that the Gateway263performs, for example. IP/IDP265health checks may be made more robust by crowdsourcing, e.g., by tracking if users are successful with MFA, or by sharing health checks performed by other Gateway Points of Presence (PoPs), etc.

In accordance with another example, an HD session may be allowed with a reduced or restricted access. A downside of deferred policy application is that in some scenarios enough damage may be done by a malicious actor after initially logging in. One option is to (temporarily) restrict the access level, e.g., in an HD Windows session, similar to Kerberos constrained delegation. Instead of allowing full access to the session, the VDA253could restrict user access in outage mode when online MFA is not possible. Full access may be restored after deferred MFA policy application and obtaining a new MFAT. If a deferred policy cannot be applied within a grace period, the session may be disconnected. Some of the restrictions may include: using Windows AppLocker polices to restrict applications that are allowed to be open; and preventing network access for the user SID, in which case the VDA253could reduce the access given to logon SID to remove a lot of privileges. Security policies may also be evaluated with evidence from the logon using Smart Access tags in some embodiments. In accordance with one example implementation: Windows OS restrictions may restrict access to network shares; contextual HD connection policy restrictions may tie with Smart Access tags including Content Data Model (CDM), clipboard, Drag-and-Drop, etc.; and restriction of double-hop access may be restricted.

Policy Tokens (PT) with more real-time context evaluation (e.g., for user activity, endpoint204analysis) can be used to enable a more dynamic MFA policy control without updating CLs or MFATs in some embodiments. More particularly, the policy token can be generated and updated frequently based on user activity (e.g., user is active versus idle and not accessing resources), endpoint analysis (IP address in known range, anti-virus software installed, etc.), device registration, and managed versus unmanaged devices. In addition, MFA policies may have different tiers. The most appropriate tier may be selected based on user context. This may include push mechanisms for PT from CLIS258to help ensure real-time or close to real-time delivery. The PT may complement the static policy in the resource CL. Further, the CL may include policy tiers specifying different categories of security restrictions, e.g., duration of the grace period, deferred policy update, etc. Also, the Gateway263and Connector264may use a PT as a selector into the different tiers in the resource CL.

MFATs are designed to be used as evidence of recent MFA, and it may be sent by the WA instance to the Gateway263and/or Connector264even after it has expired. Additional secondary “evidence” may be used for the Gateway263and/or Connector264to allow a connection without MFA. For example, this may be done for an IP address associated with previous connections (stored by the Gateway263). Latency may be another secondary evidence of MFA, e.g., a latency that is consistent with prior sessions which may be indicative of the user being in a same geographical location. Such types of evidence may similarly be applied in selecting different CL MFA policies.

Time-based One-time Password (TOTP) is one technique for generating MFA codes supported by Citrix Cloud, Google Authenticator, and other vendors. TOTP works by creating a shared secret key per user, and it allows both the client and server to generate the same MFA code using a hash function given the same secret key and synchronized clocks. In an outage of IP/IDP265, another component such as the VDA253could perform MFA, provided it has the TOTP secret key for the user. The benefit of such an approach would be the that user experience remains fairly consistent—the user would login with the same MFA code that they would normally use for authentication. Various approaches may be used for providing the secret key to the VDA253, one of which includes storing the TOTP secret key in the lease. Another approach is to encrypt the TOTP secret key with the VDA's public key before storing it in the lease. Still another approach is to cache TOTP secrets on the local host cache. Storing a second copy of the TOTP secrets provides redundancy against failure.

In accordance with another example approach, the secret TOTP key may be secured in the MFAT. More particularly, the symmetric key may be encrypted with the VDA253public key, or with a Broker260/Connector264public key. This prevents the endpoint204from seeing the secret key, but the VDA253is able to do so. The IP/IDP265encrypts the TOTP secret key with symmetric key, and encrypts the symmetric key with both the Broker260and Connector264public keys. The two instances of the encrypted symmetric keys are included in the MFAT. Upon establishing a connection via CLXMTP, the VDA253contacts the Broker260(when the Broker is online) or Connector264(when the Broker is offline) with a request to decrypt respective instances of the symmetric key. The VDA253then uses the decrypted symmetric key to decrypt the TOTP Secret Key and log the user in.

Another option for communicating the TOTP secret key is similar to the approach described above, but the symmetric key is instead encrypted with multiple Gateway PoP public keys. The Root of Trust (RoT)257already has all the Gateway PoPs public keys, so it can provide them to IP/IDP265. This would need to be done for all Gateway PoPs, and if there are many PoPs the MFAT could become relatively large. As an optional enhancement, location awareness may be used with help from a Network Location Service (NLS). NLS could provide a short list of Gateway PoPs, e.g., nearest PoP and a limited number of fallbacks. For example, if a user is in the US East coast, the public keys of the US East coast PoP and US central PoP could be used, or the public keys of all the PoPs in the US (as opposed to globally) could be used. Thus, the size of MFAT may be reduced. Upon establishing a connection via CLXMTP, the Gateway PoP receives the MFAT from the endpoint204. The Gateway PoP is able to decrypt the symmetric key with its PoP's private key and then, after establishing CLXMTP with the resolved target VDA, the symmetric key is re-encrypted with the resolved VDA's public key. The VDA253is then able to decrypt the symmetric key with its VDA private key. The VDA253then decrypts the TOTP secret key in the MFAT payload using the symmetric key. The VDA253then securely stores the TOTP secret key. When an HD connection starts, the VDA253presents a TOTP authentication challenge to the user, using the TOTP secret key. If the user successfully answers the TOTP challenge, the VDA253logs the user into the session.

Since the VDA253is able to obtain the user TOTP secret key from the MFAT, the VDA could use a library (e.g., an open source TOTP library) to perform MFA for the user. This approach may be combined with a credential provider at the VDA253to achieve SSOn, or the user could be prompted for TOTP (6-digit MFA code). The credential provider asks for the TOTP and the domain credential to perform MFA. An advantage of the TOTP approach is that all cloud components could be down, except the Gateway263for Gateway (remote) connections, yet session access may still be grated with MFA assurance.

In accordance with another example implementation, FIDO2 may be incorporated to provide still further functionality. FIDO2 is the overarching term for FIDO Alliance's newest set of specifications. FIDO2 enables users to leverage common devices to easily authenticate to online services in both mobile and desktop environments. From a security perspective, FIDO2's cryptographic login credentials are unique across every website, never leave the user's device and are never stored on a server. This security model helps eliminate the risks of phishing, different forms of password theft and replay attacks.

Using biometrics helps solve end-user convenience and privacy concerns. Users unlock cryptographic login credentials with built-in methods such as fingerprint readers or cameras on their endpoint devices204, or by leveraging easy-to-use FIDO security keys. Because FIDO cryptographic keys are unique for each internet site, they cannot be used to track users across sites. Plus, biometric data, when used, never leaves the user's device. Additionally, with respect to scalability, websites can enable FIDO2 through a JavaScript API call that is supported across leading browsers and platforms on billions of devices consumers use every day.

FIDO2 authentication to the VDA253may be facilitated with the MFAT. More particularly, a WA208user could authenticate with FIDO2 integrated with Workspace256and IP/IDP265. In an example embodiment, the authentication process may include a first (one-time) step of new user registration and credential creation, in which a FIDO2 Relying Party (RP) sends a challenge and RP information. The endpoint204uses a secure platform authenticator module to verify the user. For example, a biometrics challenge may be performed (fingerprint, iris scan, etc.), e.g. using Windows Hello. A private/public key pair is generated in a TPM on the endpoint, and an attestation object (credential) is created and signed with the private key. The RP verifies and registers (stores in a database) the credential (public key, credential ID). At this point, the credential ID could be included in a MFAT by the IP/IDP265, and the MFAT returned to the endpoint204.

Subsequently, in an online mode, the user could authenticate to Workspace256and IP/IDP265using a normal FIDO2 flow. In offline conditions, the MFAT could provide the credential ID to the VDA253using the same mechanisms as described in the TOTP flow above. The VDA253, with help from a credential provider, could perform an authentication challenge based on FIDO2 and the MFAT-derived credential ID, as follows. FIDO2 (WebAuthn) API redirection is perform over a HD connection. After requesting and receiving a challenge from the RP, the VDA253will use the MFAT-derived credential ID to build a client data hash and include it in the parameters for getting an assertion (client data hash, credential ID, RP and challenge info). The endpoint204may verify the user (biometrics, etc.), and use the supplied parameters to create and sign an assertion with its private key, then respond with the assertion to the VDA253. Furthermore, the VDA253may authenticate with the signed assertion to the RP. The RP will fetch the stored public key using the credential ID and validate the signature of the assertion using the public key, validate the client info hash, and return success if all validations succeed. An advantage of this approach is that users will continue to use a familiar FIDO2-based auth, e.g., biometric auth with Windows Hello for both WS/IP authentication (in online conditions) and session authentication (in offline conditions).

In some embodiments, a form of local authentication may optionally be applied, e.g., a PIN or biometric. However, a local auth may not be the equivalent in complexity or strength (overall security policy or preference) to the cloud-service provided MFA. Furthermore, in some embodiments a cloud-based MFA may be implemented from the VDA253. This would otherwise require MFA-related cloud services to be available, but could work if the endpoint device204Internet connection is down yet the VDA has no connectivity issues. Overall, each of the MFA options described above could be enabled based on a policy configuration to be selected by customers who may have specific requirements and preferences.

Another example approach may be implemented at the WA instance208as follows. Even when WSUI is in an offline mode (e.g., if Workspace256is down) or a specific Workspace resource feed is cached (e.g., if CVAD service is down), then based on a separate IP/IDP265health-check performed by WA208, MFA may be run and applied. This approach will work for the user if WA208is online (Internet is available) and if IP/IDP265and MFA-related services are available. The behavior could be applied based on policy. Furthermore, in some embodiments the use of CLs may optionally be restricted based on successful MFA. This may be done to prevent the use of CLs by an advanced user who may be able to bypass the WA UI or recompile the WA code, etc.

Turning to the sequence diagram290ofFIG.9, an example sequence flow for MFAT generation is now described. An authentication agent (here IP/IDP265) performs IP key bootstrapping initially upon key rotation with the RoT257by having the IP public key signed by the RoT. This takes place in parallel with the MFA flow. The WA instance208initiates MFA with its endpoint public key, the MFA flow is performed by IP/IDP265to generate the MFAT (which is user-device bound and signed by the IP public key signed by the RoT257), and the MFAT is returned to and stored by the WA instance.

Referring to the sequence diagram300ofFIG.10, a gateway policy evaluation sequence is now described. The gateway263communicates with the IP/IDP265to perform identity provider health checks, as discussed above. In parallel with the health checks, the gateway263performs policy evaluation responsive to the CLXMTP connection. This includes an evaluation of CL MFA policy from the CL, as well as of the IP/IDP265health status. Evaluating the MFA policy (with the input from a MFA policy section in the CL, the health of the Identity Provider (IDP), etc.) is what allows the Gateway263to decide to accept or reject the MFA. For instance, the policy could validate the window of time for which a previously created MFAT will be accepted, decide to reject the MFAT if the IDP status is reported as healthy (because the user should be able to redo a successful MFA), reject the MFAT if the origin IP address is not recognized, etc. As also discussed above, a check may optionally be performed to determine if MFA is required (e.g., external vs. internal connection), as well as to determine if the MFAT is valid, as also discussed above, prior to allowing the connection.

Turning to the sequence diagram310ofFIG.11, a first portion of a launch with CLs and MFAT is now described. The gateway263and RoT257perform a gateway PoP key bootstrap operation, in parallel with the gateway performing IP/IDP265health checks, as discussed above. The WA instance204communicates with Workspace256to obtain the MFAT, status and dynamic (published resource) data, and then communicates with the CLIS258to request and sync CLs and signed public keys for the endpoint device204, RoT257, and CLIS. The WA instance204stores the CLs and keys in the cache289, as noted above.

In a second portion of the launch sequence shown in the sequence flow diagram320ofFIG.12, when a user launches a published resource from the endpoint device204, a CLXMTP connection is opened with the gateway263based upon the appropriate CL and MFAT. The gateway263performs a challenge-response based upon the CL signature, date, and thumbprint validation, and optionally reads the MFA policies from the CL. In some embodiments, the gateway263may also perform MFAT signature, data, and thumbprint validation, allow/decline the CLXMTP connection with a grace period based upon a CL policy tier, IP/IDP265health check, etc., as discussed further above. Alternatively, the gateway263may open a CLXMTP connection with the VDA253, with validates and resolves the CLs, and the gateway generates a GCT and allows the WA instance208to initiate an HD connection with the VDA.

A launch with CLs and expired MFAT and a grace period when IP/IDP265is down is now described with reference to the sequence diagram330ofFIG.13. The WA208performs MFA with Workspace256to obtain and store an MFAT. In parallel, the gateway performs IP/IDP265health checks. Notwithstanding a subsequent failure of the attempted MFA with Workspace256, a user launches a published resource from the WA instance204. A CLXMTP connection is opened from the WA instance208to the gateway263with the appropriate CL(s) and expired MFAT. The gateway263performs a challenge response based upon the CL signature, date, and thumbprint validation, reads the MFA policies from the CL, and allows the CLXMTP connection with a grace period based upon the CL policy tier and identity provider health check. The gateway263opens a CLXMTP connection with the VDA253, which validates and resolves the CLs, generates a GCT, and the gateway allows the WA instance208to initiate an HD connection with the VDA.

A deferred policy update when the IP/IDP265is down is now described with reference to the flow diagram340ofFIG.14. A session is established between the WA instance208and VDA257as discussed above. When the gateway263determines that the MFA grace period has expired, it performs a health check of the IP/IDP265. When it is determined that the health information is not available (e.g., the IP/IDP265is offline or unavailable), the gateway263sends a warning to the user that the connection is about to be dropped, and shortly thereafter the HD connection is dropped.

Furthermore, a deferred policy update when the IP/IDP265is up is now described with reference to the sequence flow diagram350ofFIG.15. The steps are the same as in the sequence340until a healthy health check status is returned from the IP/IDP265, at which point the gateway256requests the WA instance208perform MFA over an HD connection, which the WA instance then does with Workspace256and stores the MFAT. Alternatively, the WA instance208may just send the MFAT and validate it at the gateway263based on the stored thumbprint and CL policies from the GCT, as discussed further above. A CLXMTP connection is initiated over an HD connection based upon the CL(s) and new MFAT, and the gateway263performs a challenge-response, reads the MFA policies from the CL, and performs MFAT signature, date and thumbprint validation. If they are all validated, the gateway263allows the HD connection to continue.

Turning now to the sequence flow diagram360ofFIG.16, generation of an MFAT with a TOTP secret key is now described. Identity provider key bootstrapping and MFA flow initiation are performed as discussed further above. Alternatively, if a TOTP secret key per user does not exist, the TOTP secret key is generated by the CLIS265. In an optional operation, the WA implicit (public IP) or explicit (GPS) location of the WA instance208may be communicated to a network location service361, which returns zone information from which the appropriate gateway PoP public keys are selected. IP/IDP265encrypts the symmetric key with the gateway PoP public key(s), and generates the MFAT including the encrypted TOTP secret key and also provides an encrypted version of the symmetric key. The MFAT is user-device bound and signed by the IP public265public key, and the MFAT is then sent to and stored by the WA instance208.

A launch with CLs and expired MFA token with a TOTP secret key when IP/IDP265is down is now described with reference to the sequence flow diagram ofFIG.17. The MFAT generation and IP/IDP265health checks are performed as described further above. Notwithstanding a subsequent failed attempt to perform MFA a user launches a published resource, which initiates a CLXMTP connection based upon the appropriate CL(s), expired MFAT and TOTP secret key. The gateway performs a challenge-response, reads the MFA policies from the CL, and validates the MFAT signature, date, and thumbprint as discussed above. When the MFAT is expired and the CL policy allows TOTP, the gateway263then decrypts the symmetric key with the gateway PoP private key, and re-encrypts the symmetric key with the VDA257and/or gateway263public keys, and allows the CLXMTP connection. The gateway263initiates a CLXMTP connection with the VDA257, which in turn validates and resolves the CLs, decrypts the symmetric key with the VDA257/gateway263private key, and stores the TOTP secret key. The gateway263then generates the Gateway Connection Ticket (CGT), with which the WA instance208may initiate the HD connection with the VDA257to access a computing session.

A new user registration to make a credential is now described with reference to the flow diagram380ofFIG.18. From a browser (or native app)382such as a WebAuthn client/user agent, a registration request is sent to a relying party383, to which a registration response is returned. The browser requests credential creation from a platform authenticator381, which verifies the user and creates the credential (e.g., by signing with a private key). Upon receiving a response, the browser382provides the registration response (credential) with the relying party383, which verifies the credential (attestation), stores it, and indicates successful completion to the browser.

An approach to authenticate a user by verifying an assertion using FIDO2 is now described with reference to the sequence flow diagram390ofFIG.19. The browser382sends an authentication request to the relying party383, to which an authentication response (with challenge options) is returned. The browser382requests an assertion be created by the platform authenticator381, which verifies the user and creates the assertion (e.g., by signing with a private key), and responds with the assertion to the browser. The browser382authenticates with the relying party383with the assertion, and the relying party looks up the public key, verifies the assertion, and informs the browser of the successful completion.

It should be noted that the above-described concepts can be applied to different CL use cases, e.g., for Web/SaaS apps, cloud storage apps, CEM native apps, etc. The various approaches discussed above are also useful for online conditions as well as existing traditional ICA file-based launches. For example, when the VDA253is being prepared for a user session (Launch and PrepareForSession call from WA→Workspace→Broker→VDA), the VDA could be informed about the security context of the user and all of the MFA policy requirements can be enforced on the VDA.

Turning to the flow diagram400ofFIG.20, a related method is now described. Beginning at Block401, the method illustratively includes, at a computing device201, receiving a connection lease and a token from a client device204, with the token being generated responsive to the client device completing MFA with a provider of MFA, at Block402, as discussed further above. The method further illustratively includes verifying, responsive to unavailability of the provider of MFA205(Block403), that the client device204has previously performed MFA based upon the token, at Block404, and connecting the client device to a computing session206with use of the connection lease and responsive to the verification that the client device has performed MFA (Block405), as also discussed further above. The method ofFIG.20illustratively concludes at Block406.

As will be appreciated by one of skill in the art upon reading the foregoing disclosure, various aspects described herein may be embodied as a device, a method or a computer program product (e.g., a non-transitory computer-readable medium having computer executable instruction for performing the noted operations or steps). Accordingly, those aspects may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects.

Furthermore, such aspects may take the form of a computer program product stored by one or more computer-readable storage media having computer-readable program code, or instructions, embodied in or on the storage media. Any suitable computer readable storage media may be utilized, including hard disks, CD-ROMs, optical storage devices, magnetic storage devices, and/or any combination thereof.

Many modifications and other embodiments will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is understood that the foregoing is not to be limited to the example embodiments, and that modifications and other embodiments are intended to be included within the scope of the appended claims.