Patent Publication Number: US-11663032-B2

Title: Techniques for securing virtual machines by application use analysis

Description:
This application is a continuation of U.S. application Ser. No. 17/330,998 (now allowed), filed May 26, 2021, which is a continuation of U.S. application Ser. No. 16/585,967 (now U.S. Pat. No. 11,431,735), filed Sep. 27, 2019, which claims the benefit of U.S. Provisional Application No. 62/797,718 filed on Jan. 28, 2019, the contents of each of which are hereby incorporated by reference in their entireties. 
    
    
     TECHNICAL FIELD 
     This disclosure relates generally to cyber-security systems and, more specifically, to techniques for securing virtual machines. 
     BACKGROUND 
     Organizations have increasingly adapted their applications to be run from multiple cloud computing platforms. Some leading public cloud service providers include Amazon®, Microsoft®, Google®, and the like. 
     Virtualization is a key role in a cloud computing, allowing multiple applications and users to share the same cloud computing infrastructure. For example, a cloud storage service can maintain data of multiple different users. 
     In one instance, virtualization can be achieved by means of virtual machines. A virtual machine emulates a number of “computers” or instances, all within a single physical device. In more detail, virtual machines provide the ability to emulate a separate operating system (OS), also referred to as a guest OS, and therefore a separate computer, from an existing OS (the host). This independent instance is typically isolated as a completely standalone environment. 
     Modern virtualization technologies are also adapted by cloud computing platforms. Examples for such technologies include virtual machines, software containers, and serverless functions. With their computing advantages, applications and virtual machines running on top of virtualization technologies are also vulnerable to some cyber threats. For example, virtual machines can execute vulnerable software applications or infected operating systems. 
     Protection of a cloud computing infrastructure, and particularly of virtual machines can be achieved via inspection of traffic. Traditionally, traffic inspection is performed by a network device connected between a client and a server (deployed in a cloud computing platform or a data center) hosting virtual machines. Traffic inspection may not provide an accurate indication of the security status of the server due to inherent limitations, such as encryption and whether the necessary data is exposed in the communication. 
     Furthermore, inspection of computing infrastructure may be performed by a network scanner deployed out of path. The scanner queries the server to determine if the server executes an application that possess a security threat, such as vulnerability in the application. The disadvantage of such a scanner is that the server may not respond to all queries by the scanner, or not expose the necessary data in the response. Further, the network scanner usually communicates with the server, and the network configuration may prevent it. In addition, some types of queries may require credentials to access the server. Such credentials may not be available to the scanner. 
     Traffic inspection may also be performed by a traffic monitor that listens to traffic flows between clients and the server. The traffic monitor can detect some cyber threats, e.g., based on the volume of traffic. However, the monitor can detect threats only based on the monitored traffic. For example, misconfiguration of the server may not be detected by the traffic monitor. As such, traffic monitoring would not allow detection of vulnerabilities in software executed by the server. 
     To overcome the limitations of traffic inspection solutions, some cyber-security solutions, such as vulnerability management and security assessment solutions are based on agents installed in each server in a cloud computing platform or data center. Using agents is a cumbersome solution for a number of reasons, including IT resources management, governance, and performance. For example, installing agents in a large data center may take months. 
     It would therefore be advantageous to provide a security solution that would overcome the deficiencies noted above. 
     SUMMARY 
     A summary of several example embodiments of the disclosure follows. This summary is provided for the convenience of the reader to provide a basic understanding of such embodiments and does not wholly define the breadth of the disclosure. This summary is not an extensive overview of all contemplated embodiments, and is intended to neither identify key or critical elements of all embodiments nor to delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more embodiments in a simplified form as a prelude to the more detailed description that is presented later. For convenience, the term “some embodiments” or “certain embodiments” may be used herein to refer to a single embodiment or multiple embodiments of the disclosure. 
     Certain embodiments disclosed herein include a method for securing virtual cloud assets in a cloud computing environment against cyber threats, comprising: determining a location of a snapshot of at least one virtual disk of a protected virtual cloud asset, wherein the virtual cloud asset is instantiated in the cloud computing environment; accessing the snapshot of the virtual disk based on the determined location; analyzing the snapshot of the protected virtual cloud asset to detect potential cyber threats risking the protected virtual cloud asset; and alerting detected potential cyber threats based on a determined priority. 
     Certain embodiments disclosed herein also include a non-transitory computer readable medium having stored thereon instructions for causing a processing circuitry to execute a process, the process comprising: determining a location of a snapshot of at least one virtual disk of a protected virtual cloud asset, wherein the virtual cloud asset is instantiated in the cloud computing environment; accessing the snapshot of the virtual disk based on the determined location; analyzing the snapshot of the protected virtual cloud asset to detect potential cyber threats risking the protected virtual cloud asset; and alerting detected potential cyber threats based on a determined priority. 
     Certain embodiments disclosed herein also include a system for securing virtual cloud assets in a cloud computing environment against cyber threats, comprising: a processing circuitry; and a memory, the memory containing instructions that, when executed by the processing circuitry, configure the system to: determine a location of a snapshot of at least one virtual disk of a protected virtual cloud asset, wherein the virtual cloud asset is instantiated in the cloud computing environment; access the snapshot of the virtual disk based on the determined location; analyze the snapshot of the protected virtual cloud asset to detect potential cyber threats risking the protected virtual cloud asset; and alert detected potential cyber threats based on a determined priority. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other objects, features, and advantages of the disclosed embodiments will be apparent from the following detailed description taken in conjunction with the accompanying drawings. 
         FIGS.  1 A and  1 B  are network diagrams utilized to describe the various embodiments. 
         FIG.  2    is a flowchart illustrating a method detecting cyber threats, including potential vulnerabilities in virtual machines executed in a cloud computing platform according to some embodiments. 
         FIG.  3    is an example block diagram of the security system according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     It is important to note that the embodiments disclosed herein are only examples of the many advantageous uses of the innovative teachings herein. In general, statements made in the specification of the present application do not necessarily limit any of the various claimed embodiments. Moreover, some statements may apply to some inventive features but not to others. In general, unless otherwise indicated, singular elements may be in plural and vice versa with no loss of generality. In the drawings, like numerals refer to like parts through several views. 
       FIGS.  1 A and  1 B  show an example network diagram  100  utilized to describe the various embodiments. A cloud computing platform  110  is communicably connected to a network  120 . Examples of the cloud computing platform  110  may include a public cloud, a private cloud, a hybrid cloud, and the like. Examples for a public cloud, but are not limited to, AWS® by Amazon®, Microsoft Azure®, Google Cloud®, and the like. In some configurations, the disclosed embodiments operable in on premise virtual machines environments. The network  120  may be the Internet, the world-wide-web (WWW), a local area network (LAN), a wide area network (WAN), and other networks. 
     The arrangement of the example cloud computing platform  110  is shown in  FIG.  1 B . As illustrated, the platform  110  includes a server  115  and a storage  117 , serving as the storage space for the server  115 . The server  115  is a physical device hosting at least one virtual machine (VM)  119 . The VM  119  is a protected VM, which may be any virtual cloud asset including, but not limited to, a software container, a micro-service, a serverless function, and the like. 
     The storage  117  emulates virtual discs for the VMs executed in by the server  115 . The storage  117  is typically connected to the server  115  through a high-speed connection, such as optic fiber allowing fast retrieval of data. In other configurations, the storage  117  may be part of the server  115 . In this example illustrated in  FIG.  1 B , virtual disk  118 - 1  is allocated for the VM  119 . The server  115 , and hence the VM  119 , may be executed in a client environment  130  within the platform  110 . 
     The client environment  130  is an environment within the cloud computing platform  110  utilized to execute cloud-hosted applications of the client. A client may belong to a specific tenant. In some example embodiment, the client environment  130  may be part of a virtualized environment or on-premises virtualization environment, such as a VMware® based solution. 
     Also deployed in the cloud computing platform  110  is a security system  140  configured to perform the various disclosed embodiments. In some embodiments, the system  140  may be part of the client environment  130 . In an embodiment, the security system  140  may be realized as a physical machine configured to execute a plurality of virtual instances, such as, but not limited to virtual machines executed by a host server. In yet another embodiment, the security system  140  may be realized as a virtual machine executed by a host server. Such a host server is a physical machine (device) and may be either the server  115 , a dedicated server, a different shared server, or another virtualization-based computing entity, such as a serverless function. 
     In an embodiment, the interface between the client environment  130  and the security system  140  can be realized using APIs or services provided by the cloud computing platform  110 . For example, in AWS, a cross account policy service can be utilized to allow interfacing the client environment  130  with the security system  140 . 
     In the deployment, illustrated in  FIG.  1   , the configuration of resources of the cloud computing platform  110  is performed by means of the management console  150 . As such, the management console  150  may be queried on the current deployment and settings of resources in the cloud computing platform  110 . Specifically, the management console  150  may be queried, by the security system  140 , about as the location (e.g., virtual address) of the virtual disk  118 - 1  in the storage  117 . The system  140  is configured to interface with the management console  150  through, for example, an API. 
     In some example embodiments, the security system  140  may further interface with the cloud computing platform  110  and external systems  170 . The external systems may include intelligence systems, security information and event management (SIEM) systems, and mitigation tools. The external intelligence systems may include common vulnerabilities and exposures (CVE®) databases, reputation services, security systems (providing feeds on discovered threats), and so on. The information provided by the intelligence systems may detect certain known vulnerabilities identified in, for example, a CVE database. 
     According to the disclosed embodiments, the security system  140  is configured to detect vulnerabilities and other cyber threats related to the execution VM  119 . The detection is performed while the VM  119  is live, without using any agent installed in the server  115  or the VM  119 , and without relying on cooperation from VM  119  guest OS. Specifically, the security system  140  can scan and detect vulnerable software, non-secure configuration, exploitation attempts, compromised asserts, data leaks, data mining, and so on. The security system  140  may be further utilized to provide security services, such as incident response, anti-ransomware, and cyber insurance by accessing the security posture. 
     In some embodiments, the security system  140  is configured to query the cloud management console  150  for the address of the virtual disk  118 - 1  serving the VM  119  and a location of the snapshot. A VM&#39;s snapshot is a copy of the machine&#39;s virtual disk (or disk file) at a given point in time. Snapshots provide a change log for the virtual disk and are used to restore a VM to a particular point in time when a failure error occurs. Typically, any data that was writable on a VM becomes read-only when the snapshot is taken. Multiple snapshots of a VM can be created at multiple possible point-in-time restore points. When a VM reverts to a snapshot, current disk and memory states are deleted and the snapshot becomes the new parent snapshot for that VM. 
     The snapshot of the VM  119  is located and may be saved from the virtual disk  118 - 1  is accessed by the system  140 . In an embodiment, the VM&#39;s  119  snapshot may be copied to the system  140 . If such a snapshot does not exist, the system  140  may take a new snapshot, or request such an action. The snapshots may be taken at a predefined schedule or upon predefined events (e.g., a network event or abnormal event). Further, the snapshots may be accessed or copied on a predefined schedule or upon predefined events. It should be noted that when the snapshot is taken or copied, the VM  119  still runs. 
     It should be noted that the snapshot of the virtual disk  118 - 1  may not be necessary stored in the storage  117 , but for ease of the discussion it is assumed that the snapshot is saved in the storage  117 . It should be further noted that the snapshot is being accessed without cooperation of the guest, virtual OS of the virtual machine. 
     The snapshot is parsed and analyzed by the security system  140  to detect vulnerabilities. This analysis of the snapshot does not require any interaction and/or information from the VM  119 . As further demonstrated herein, the analysis of the snapshot by the system  140  does not require any agent installed on the server  115  or VM  119 . 
     Various techniques can be utilized to analyze the snapshots, depending on the type of vulnerability and cyber threats to be detected. Following are some example embodiments for techniques that may be implemented by the security system  140 . 
     In an embodiment, the security system  140  is configured to detect whether there is vulnerable code executed by the VM  119 . The VM  119  being checked may be running, paused, or shutdown. To this end, the security system  140  is configured to match installed application lists, with their respective versions, to a known list of vulnerable applications. Further, the security system  140  may be configured to match the application files, either directly (using binary comparison) or by computing a cryptographic hash against database of files in vulnerable applications. The matching may be also on sub-modules of an application. Alternatively, the security system  140  may read installation logs of package managers used to install the packages of the application. 
     In yet another embodiment, the security system  140  is configured to verify whether the vulnerability is relevant to the VM  119 . For example, if there is a vulnerable version or module not in use, the priority of that issue is reduced dramatically. 
     To this end, the security system  140  may be configured to check the configuration files of the applications and operating system of the VM  119 ; to verify access times to files by the operating system; and/or to analyze the active application and/or system logs in order to deduce what applications and modules are running. 
     In yet another embodiment, the security system  140  may instantiate a copy of the VM  119  and/or a subset of applications of the VM  119  on the server  115  or a separate server and monitor all activity performed by the instance of the VM. The execution of the instance of the VM is an isolated sandbox, which can be a full VM or subset of it, such as a software container (e.g., Docker® container) or another virtualized instances. The monitored activity may be further analyzed to determine abnormality. Such analysis may include monitoring of API activity, process creation, file activity, network communication, registry changes, and active probing of the said subset in order to assess its security posture. This may include, but not limited to, actively communicating with the VM  119 , using either legitimate communicate and/or attack attempts, to assess its posture and by that deriving the security posture of the entire VM  119 . 
     In order to determine if the vulnerability is relevant to the VM  119 , the security system  140  is configured to analyze the machine memory, as reflected in the page file. The page file is saved in the snapshot and extends how much system-committed memory (also known as “virtual memory”) a system can back. In an embodiment, analyzing the page file allows deduction of running applications and modules by the VM  119 . 
     In an embodiment, the security system  140  is configured to read process identification number (PID) files and check their access or write times, which are matched against process descriptors. The PID can be used to deduce which processes are running, and hence the priority of vulnerabilities detected in processes existing on the disk. It should be noted the PID files are also maintained in the snapshot. 
     In yet another embodiment, the security system  140  is configured to detect cyber threats that do not represent vulnerabilities. For example, the security system  140  may detect and alert on sensitive data not being encrypted on the logical disk, private keys found on the disks, system credentials stored clearly on the disk, risky application features (e.g., support of weak cipher suites or authentication methods), weak passwords, weak encryption schemes, a disable address space layout randomization (ASLR) feature, suspicious manipulation to a boot record, suspicious PATH, LD_LIBRARY_PATH, or LD_PRELOAD definitions, services running on startup, and the like. 
     In an embodiment, the security system  140  may further monitor changes in sensitive machine areas, and alert on unexpected changes (e.g., added or changed application files without installation). In an example embodiment, this can be achieved by computing a cryptographic hash of the sensitive areas in the virtual disk and checking for differences over time. 
     In some embodiments, the detected cyber threats (including vulnerabilities) are reported to a user console  180  and/or a security information and event management (SIEM) system (not shown). The reported cyber threats may be filtered or prioritized based in part on their determined risk. Further, the reported cyber threats may be filtered or prioritized based in part on the risk level of the machine. This also reduces the number of alerts reported to the user. 
     In an embodiment, any detected cyber threats related to sensitive data (including personally identifiable information, PII) is reported at a higher priority. In an embodiment, such data is determined by searching for the PII, analyzing the application logs to determine whether the machine accessed PII/PII containing servers, or whether the logs themselves contain PII, and searching the machine memory, as reflected in the page file, for PII. 
     In an embodiment, the security system  140  may determine the risk of the VM  119  based on communication with an untrusted network. This can be achieved by analyzing the VM&#39;s  119  logs as saved in the virtual disk and can be derived from the snapshot. 
     In an example embodiment, the security system  140  may cause an execution of one or more mitigation actions. Examples of such actions may include blocking traffic from untrusted networks, halting the operation of the VM, quarantining an infected VM, and the like. The mitigation actions may be performed by a mitigation tool and not the system  140 . 
     It should be noted that the example implementation shown in  FIG.  1    is described with respect to a single cloud computing platform  110  hosting a single VM  119  in a single server  115 , merely for simplicity purposes and without limitation on the disclosed embodiments. Typically, virtual machines are deployed and executed in a single cloud computing platform, a virtualized environment, or data center and can be protected without departing from the scope of the disclosure. It should be further noted that the disclosed embodiments can operate using multiple security systems  140 , each of which may operate in a different client environment. 
       FIG.  2    shows an example flowchart  200  illustrating a method for detecting cyber threats including potential vulnerabilities in virtual machines executed in a cloud computing platform according to some embodiments. The method may be performed by the security system  140 . 
     At S 210 , a request, for example, to scan a VM for vulnerabilities is received. The request may be received, or otherwise triggered every predefined time interval or upon detection of an external event. An external event may be a preconfigured event, such as a network event or abnormal event including, but not limited to, changes to infrastructure such as instantiation of an additional container on existing VM, image change on a VM, new VM created, unexpected shutdowns, access requests from unauthorized users, and the like. The request may at least designate an identifier of the VM to be scanned. 
     At S 220 , a location of a snapshot of a virtual disk of the VM to be scanned is determined. In an embodiment, S 220  may include determining the virtual disk allocated for the VM, prior to determining the location of the snapshot. As noted above, this can be achieved by querying a cloud management console. At S 230 , a snapshot of the virtual disk is accessed, or otherwise copied. 
     At S 240 , the snapshot is analyzed to detect cyber threats and potential vulnerabilities. S 240  may be also include detecting cyber threats that do not represent vulnerabilities. Examples for cyber threats and vulnerabilities are provided above. 
     In an embodiment, S 240  may include comparing the snapshot to some baseline, which may include, but is not limited to, a copy of the image used to create the VM, (e.g., lists of applications, previous snapshots), cryptographic hashes gathered in the previous scan, analyzing logs of the VMs, instantiating a copy of the VM and executing the instance or applications executed by the VM in a sandbox, analyzing the machine memory, as reflected in the page file, or any combination of these techniques. Some example embodiments for analyzing the snapshots and the types of detected vulnerabilities and threats are provided above. 
     At S 250 , the detected cyber threats and/or vulnerabilities are reported, for example, as alerts. In an embodiment, S 250  may include filtering and prioritizing the reported alerts. In an embodiment, the prioritization is based, in part, on the risk level of a vulnerable machine. The filtering and prioritizing allow to reduce the number of alerts reported to the user. The filtering can be done performed on external intelligence on the likelihood of this vulnerability being exploited, analyzing the machine configuration in order to deduce the vulnerability relevancy, and correlating the vulnerability with the network location, and by weighting the risk of this machine being taken over by the attacker by taking into consideration the criticality of the machine in the organization based by the contents stored or other assets accessible from the VM  110 . 
     At optional S 260 , a mitigation action may be triggered to mitigate a detected threat or vulnerability. A mitigation action may be executed by a mitigation tool and triggered by the system  140 . Such an action may include blocking traffic from untrusted networks, halting the operation of the VM, quarantining an infected VM, and the like. 
       FIG.  3    is an example block diagram of the security system  140  according to an embodiment. The security system  140  includes a processing circuitry  310  coupled to a memory  320 , a storage  330 , and a network interface  340 . In an embodiment, the components of the security system  140  may be communicatively connected via a bus  360 . 
     The processing circuitry  310  may be realized as one or more hardware logic components and circuits. For example, and without limitation, illustrative types of hardware logic components that can be used include field programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), system-on-a-chip systems (SOCs), general-purpose microprocessors, microcontrollers, digital signal processors (DSPs), and the like, or any other hardware logic components that can perform calculations or other manipulations of information. 
     The memory  310  may be volatile (e.g., RAM, etc.), non-volatile (e.g., ROM, flash memory, etc.), or a combination thereof. In one configuration, computer readable instructions to implement one or more embodiments disclosed herein may be stored in the storage  330 . 
     In another embodiment, the memory  320  is configured to store software. Software shall be construed broadly to mean any type of instructions, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Instructions may include code (e.g., in source code format, binary code format, executable code format, or any other suitable format of code). The instructions, when executed by the one or more processors, cause the processing circuitry  310  to perform the various processes described herein. Specifically, the instructions, when executed, cause the processing circuitry  310  to determine over-privileged roles vulnerabilities in serverless functions. 
     The storage  330  may be magnetic storage, optical storage, and the like, and may be realized, for example, as flash memory or other memory technology, CD-ROM, Digital Versatile Disks (DVDs), hard-drives, SSD, or any other medium which can be used to store the desired information. The storage  330  may store communication consumption patterns associated with one or more communications devices. 
     The network interface  340  allows the security system  140  to communicate with the external systems, such as intelligence systems, SIEM systems, mitigation systems, a cloud management console, a user console, and the like. 
     It should be understood that the embodiments described herein are not limited to the specific architecture illustrated in  FIG.  3   , and other architectures may be equally used without departing from the scope of the disclosed embodiments. 
     The various embodiments disclosed herein can be implemented as hardware, firmware, software, or any combination thereof. Moreover, the software is preferably implemented as an application program tangibly embodied on a program storage unit or computer readable medium consisting of parts, or of certain devices and/or a combination of devices. The application program may be uploaded to, and executed by, a machine comprising any suitable architecture. Preferably, the machine is implemented on a computer platform having hardware such as one or more central processing units (“CPUs”), a memory, and input/output interfaces. The computer platform may also include an operating system and microinstruction code. The various processes and functions described herein may be either part of the microinstruction code or part of the application program, or any combination thereof, which may be executed by a CPU, whether or not such a computer or processor is explicitly shown. In addition, various other peripheral units may be connected to the computer platform such as an additional data storage unit and a printing unit. Furthermore, a non-transitory computer readable medium is any computer readable medium except for a transitory propagating signal. 
     As used herein, the phrase “at least one of” followed by a listing of items means that any of the listed items can be utilized individually, or any combination of two or more of the listed items can be utilized. For example, if a system is described as including “at least one of A, B, and C,” the system can include A alone; B alone; C alone; A and B in combination; B and C in combination; A and C in combination; or A, B, and C in combination. 
     All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the principles of the disclosed embodiment and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the disclosed embodiments, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure.