| ID | Name |
|---|---|
| T1556.001 | Domain Controller Authentication |
| T1556.002 | Password Filter DLL |
| T1556.003 | Pluggable Authentication Modules |
| T1556.004 | Network Device Authentication |
| T1556.005 | Reversible Encryption |
| T1556.006 | Multi-Factor Authentication |
| T1556.007 | Hybrid Identity |
| T1556.008 | Network Provider DLL |
| T1556.009 | Conditional Access Policies |
Adversaries may patch the authentication process on a domain controller to bypass the typical authentication mechanisms and enable access to accounts.
Malware may be used to inject false credentials into the authentication process on a domain controller with the intent of creating a backdoor used to access any user’s account and/or credentials (ex: Skeleton Key). Skeleton key works through a patch on an enterprise domain controller authentication process (LSASS) with credentials that adversaries may use to bypass the standard authentication system. Once patched, an adversary can use the injected password to successfully authenticate as any domain user account (until the the skeleton key is erased from memory by a reboot of the domain controller). Authenticated access may enable unfettered access to hosts and/or resources within single-factor authentication environments.[1]
| ID | Name | Description |
|---|---|---|
| G0114 | Chimera |
Chimera's malware has altered the NTLM authentication program on domain controllers to allow Chimera to login without a valid credential.[2] |
| S0007 | Skeleton Key |
Skeleton Key is used to patch an enterprise domain controller authentication process with a backdoor password. It allows adversaries to bypass the standard authentication system to use a defined password for all accounts authenticating to that domain controller.[1] |
| ID | Mitigation | Description |
|---|---|---|
| M1032 | Multi-factor Authentication |
Integrating multi-factor authentication (MFA) as part of organizational policy can greatly reduce the risk of an adversary gaining control of valid credentials that may be used for additional tactics such as initial access, lateral movement, and collecting information. MFA can also be used to restrict access to cloud resources and APIs. |
| M1026 | Privileged Account Management |
Audit domain and local accounts as well as their permission levels routinely to look for situations that could allow an adversary to gain wide access by obtaining credentials of a privileged account. [3] [4] These audits should also include if default accounts have been enabled, or if new local accounts are created that have not be authorized. Follow best practices for design and administration of an enterprise network to limit privileged account use across administrative tiers. [5] |
| M1025 | Privileged Process Integrity |
Enabled features, such as Protected Process Light (PPL), for LSA.[6] |
| M1017 | User Training |
Train users to recognize and handle suspicious email attachments. Emphasize the importance of caution when opening attachments from unknown or unexpected sources, even if they appear legitimate. Implement email warning banners to alert users about emails originating from outside the organization or containing attachments, reinforcing awareness and helping users identify potential spearphishing attempts. |
| ID | Name | Analytic ID | Analytic Description |
|---|---|---|---|
| DET0271 | Detect Domain Controller Authentication Process Modification (Skeleton Key) | AN0757 |
Detects anomalous process access to LSASS on domain controllers, suspicious module loads of authentication DLLs, and registry or file modifications indicative of Skeleton Key–style patching. Correlates LSASS access attempts with subsequent abnormal logon activity patterns. |