Detection rules › Sigma
Directory Service Restore Mode(DSRM) Registry Value Tampering
Detects changes to "DsrmAdminLogonBehavior" registry value. During a Domain Controller (DC) promotion, administrators create a Directory Services Restore Mode (DSRM) local administrator account with a password that rarely changes. The DSRM account is an “Administrator” account that logs in with the DSRM mode when the server is booting up to restore AD backups or recover the server from a failure. Attackers could abuse DSRM account to maintain their persistence and access to the organization's Active Directory. If the "DsrmAdminLogonBehavior" value is set to "0", the administrator account can only be used if the DC starts in DSRM. If the "DsrmAdminLogonBehavior" value is set to "1", the administrator account can only be used if the local AD DS service is stopped. If the "DsrmAdminLogonBehavior" value is set to "2", the administrator account can always be used.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Persistence | T1556 Modify Authentication Process |
| Defense Evasion | T1556 Modify Authentication Process |
| Credential Access | T1556 Modify Authentication Process |
Event coverage
| Provider | Event ID | Title |
|---|---|---|
| Sysmon | 13 | RegistryEvent (Value Set) |
Stages and Predicates
Stage 1: selection
TargetObject|endswith: '\Control\Lsa\DsrmAdminLogonBehavior'
Stage 2: not 1 of filter_main_default_value
Details: 'DWORD (0x00000000)'
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
Details | eq |
|
TargetObject | ends_with |
|