Query: Outbound C2 pattern associated with Hybrid Identity
Matching passage: T1556.007 Hybrid Identity. Tactics: defense impairment, persistence, credential access. Description: Adversaries may patch, modify, or otherwise backdoor cloud authentication processes that are tied to on-premises user identities in order to bypass typical authentication mechanisms, access credentials, and enable persistent access to accounts. Many organizations maintain hybrid user and device identities that are shared between on-premises and cloud-based environments. These can be maintained in a number of ways. For example, Microsoft Entra ID includes three options for synchronizing identities between Active Directory and Entra ID(Citation: Azure AD Hybrid Identity): * Password Hash Synchronization (PHS), in which a privileged on-premises account synchronizes user password hashes between Active Directory and Entra ID, allowing authentication to Entra ID to take place entirely in the cloud * Pass Through Authentication (PTA), in which Entra ID authentication attempts are forwarded to an on-premises PTA agent, which validates the credentials against Active Directory * Active Directory Federation Services (AD FS), in which a trust relationship is established between Active Directory and Entra ID AD FS can also be used with other SaaS and cloud platforms such as AWS and GCP, which will hand off the authentication process to AD FS and receive a token containing the hybrid users’ identity and privileges. By modifying authentication processes tied to hybrid identities, an adversary may be able to establish persistent privileged access to cloud resources. For example, adversaries who compromise an on-premises server running a PTA agent may inject a malicious DLL into the `AzureADConnectAuthenticationAgentService` process that authorizes all attempts to authenticate to Entra ID, as well as records user credentials.(Citation: Azure AD Connect for Read Teamers)(Citation: AADInternals Azure AD On-Prem to Cloud) In environments using AD FS, an adversary may edit the `Microsoft.IdentityServer.Servicehost` configuration file to load a malicious DLL that generates authentication
Near-miss passage: T1556.008 Network Provider DLL. Tactics: defense impairment, persistence, credential access. Description: Adversaries may register malicious network provider dynamic link libraries (DLLs) to capture cleartext user credentials during the authentication process. Network provider DLLs allow Windows to interface with specific network protocols and can also support add-on credential management functions.(Citation: Network Provider API) During the logon process, Winlogon (the interactive logon module) sends credentials to the local `mpnotify.exe` process via RPC. The `mpnotify.exe` process then shares the credentials in cleartext with registered credential managers when notifying that a logon event is happening.(Citation: NPPSPY - Huntress)(Citation: NPPSPY Video)(Citation: NPLogonNotify) Adversaries can configure a malicious network provider DLL to receive credentials from `mpnotify.exe`.(Citation: NPPSPY) Once installed as a credential manager (via the Registry), a malicious DLL can receive and save credentials each time a user logs onto a Windows workstation or domain via the `NPLogonNotify()` function.(Citation: NPLogonNotify) Adversaries may target planting malicious network provider DLLs on systems known to have increased logon activity and/or administrator logon activity, such as servers and domain controllers.(Citation: NPPSPY - Huntress)