Direct Autorun Keys Modification

Severity: medium
Author: Victor Sergeev, Daniil Yugoslavskiy, oscd.community, Swachchhanda Shrawan Poudel (Nextron Systems)
Source: upstream

Detects direct modification of autostart extensibility point (ASEP) in registry using reg.exe.

MITRE ATT&CK coverage

Tactic	Techniques
Persistence	`T1547.001` Boot or Logon Autostart Execution: Registry Run Keys / Startup Folder
Privilege Escalation	`T1547.001` Boot or Logon Autostart Execution: Registry Run Keys / Startup Folder

Event coverage

Provider	Event ID	Title
Sysmon	1	Process creation

Stages and Predicates

Stage 1: `all of selection_img`

or:
Image|endswith: '\reg.exe'
OriginalFileName: reg.exe

Stage 2: `all of selection_cli_add`

CommandLine|contains: add

Stage 3: `all of selection_cli_keys`

or:
CommandLine|contains: '\software\Microsoft\Windows NT\CurrentVersion\Windows'
CommandLine|contains: '\software\Microsoft\Windows NT\CurrentVersion\Winlogon\Shell'
CommandLine|contains: '\software\Microsoft\Windows NT\CurrentVersion\Winlogon\Userinit'
CommandLine|contains: '\software\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run'
CommandLine|contains: '\software\Microsoft\Windows\CurrentVersion\Run'
CommandLine|contains: '\software\WOW6432Node\Microsoft\Windows\CurrentVersion\Run'
CommandLine|contains: '\system\CurrentControlSet\Control\SafeBoot\AlternateShell'

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	`\software\Microsoft\Windows NT\CurrentVersion\Windows` `\software\Microsoft\Windows NT\CurrentVersion\Winlogon\Shell` `\software\Microsoft\Windows NT\CurrentVersion\Winlogon\Userinit` `\software\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run` `\software\Microsoft\Windows\CurrentVersion\Run` `\software\WOW6432Node\Microsoft\Windows\CurrentVersion\Run` `\system\CurrentControlSet\Control\SafeBoot\AlternateShell` `add` corpus 16 (sigma 16)
`Image`	ends_with	`\reg.exe` corpus 46 (sigma 46)
`OriginalFileName`	eq	`reg.exe` corpus 29 (sigma 29)