Adversaries may disable or modify multi-factor authentication (MFA) mechanisms to enable persistent access to compromised accounts.
Once adversaries have gained access to a network by either compromising an account lacking MFA or by employing an MFA bypass method such as Multi-Factor Authentication Request Generation, adversaries may leverage their access to modify or completely disable MFA defenses. This can be accomplished by abusing legitimate features, such as excluding users from Azure AD Conditional Access Policies, registering a new yet vulnerable/adversary-controlled MFA method, or by manually patching MFA programs and configuration files to bypass expected functionality.(Citation: Mandiant APT42)(Citation: Azure AD Conditional Access Exclusions)
For example, modifying the Windows hosts file (C:\windows\system32\drivers\etc\hosts) to redirect MFA calls to localhost instead of an MFA server may cause the MFA process to fail. If a "fail open" policy is in place, any otherwise successful authentication attempt may be granted access without enforcing MFA. (Citation: Russians Exploit Default MFA Protocol - CISA March 2022)
Depending on the scope, goals, and privileges of the adversary, MFA defenses may be disabled for individual accounts or for all accounts tied to a larger group, such as all domain accounts in a victim's network environment.(Citation: Russians Exploit Default MFA Protocol - CISA March 2022)
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 | T1556.006 | Multi-Factor Authentication |
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.
Windows Hello utilizes passkeys which helps protect against the risk of credentials being stored in files by eliminating the need for passwords.
References
|