Detection rules › Sigma
Suspicious ScreenSave Change by Reg.exe
Adversaries may establish persistence by executing malicious content triggered by user inactivity. Screensavers are programs that execute after a configurable time of user inactivity and consist of Portable Executable (PE) files with a .scr file extension
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Persistence | T1546.002 Event Triggered Execution: Screensaver |
| Privilege Escalation | T1546.002 Event Triggered Execution: Screensaver |
Event coverage
| Provider | Event ID | Title |
|---|---|---|
| Sysmon | 1 | Process creation |
| Security-Auditing | 4688 | A new process has been created. |
Stages and Predicates
Stage 1: selection_reg
or:
CommandLine|contains: 'HKCU\Control Panel\Desktop'
CommandLine|contains: 'HKEY_CURRENT_USER\Control Panel\Desktop'
Image|endswith: '\reg.exe'
Stage 2: 1 of selection_option_1
CommandLine|contains: '/d 1'
CommandLine|contains: '/f'
CommandLine|contains: '/t REG_SZ'
CommandLine|contains: '/v ScreenSaveActive'
Stage 3: 1 of selection_option_2
CommandLine|contains: '/d '
CommandLine|contains: '/f'
CommandLine|contains: '/t REG_SZ'
CommandLine|contains: '/v ScreenSaveTimeout'
Stage 4: 1 of selection_option_3
CommandLine|contains: '/d 0'
CommandLine|contains: '/f'
CommandLine|contains: '/t REG_SZ'
CommandLine|contains: '/v ScreenSaverIsSecure'
Stage 5: 1 of selection_option_4
CommandLine|contains: .scr
CommandLine|contains: '/d '
CommandLine|contains: '/f'
CommandLine|contains: '/t REG_SZ'
CommandLine|contains: '/v SCRNSAVE.EXE'
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 |
|---|---|---|
CommandLine | match |
|
Image | ends_with |
|