Adversaries may register malicious password filter dynamic link libraries (DLLs) into the authentication process to acquire user credentials as they are validated.
Windows password filters are password policy enforcement mechanisms for both domain and local accounts. Filters are implemented as DLLs containing a method to validate potential passwords against password policies. Filter DLLs can be positioned on local computers for local accounts and/or domain controllers for domain accounts. Before registering new passwords in the Security Accounts Manager (SAM), the Local Security Authority (LSA) requests validation from each registered filter. Any potential changes cannot take effect until every registered filter acknowledges validation.
Adversaries can register malicious password filters to harvest credentials from local computers and/or entire domains. To perform proper validation, filters must receive plain-text credentials from the LSA. A malicious password filter would receive these plain-text credentials every time a password request is made.(Citation: Carnal Ownage Password Filters Sept 2013)
View in MITRE ATT&CK®| Capability ID | Capability Description | Mapping Type | ATT&CK ID | ATT&CK Name | Notes |
|---|---|---|---|---|---|
| intel-ptt | Intel Platform Trust Technology | Win 11, ESS/Hello | T1556.002 | Password Filter DLL |
Comments
Windows Hello ESS authentication leverages virtual sandbox(Intel VT-X) to protect authentication data to significantly reduce the risk of brute force attacks on passwords, as biometrics typically require physical presence or biometric data that cannot be easily guessed or replicated. It uses the TPM (Intel PTT) to store authentication data including public/private key pairs. Windows Hello also includes Passkeys, a passwordless authentication option that generates public/private key pair with the public key shared with the service requiring authentication and the private key stored in the TPM, which is only released after authentication locally on the device using either a biometric factor such as fingerprint, facial recognition, or a PIN. Windows Hello helps protect against the risk of credentials being stored in files by eliminating the need for passwords in many authentication scenarios.
Enhanced Sign-In Security (ESS) will prevent unauthorized processes from requesting credentials since it runs in Virtual Trust Level 1.
Windows Hello helps protect against the risk of credentials being stored in files by eliminating the need for passwords.
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