Reg Add Suspicious Paths

Severity: high
Author: frack113, Nasreddine Bencherchali (Nextron Systems)
Source: upstream

Detects when an adversary uses the reg.exe utility to add or modify new keys or subkeys

MITRE ATT&CK coverage

Tactic	Techniques
Persistence	`T1112` Modify Registry
Defense Evasion	`T1112` Modify Registry, `T1562.001` Impair Defenses: Disable or Modify Tools

Event coverage

Provider	Event ID	Title
Sysmon	1	Process creation

Stages and Predicates

Stage 1: `all of selection_reg`

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

Stage 2: `all of selection_path`

or:
CommandLine|contains: '\AppDataLow\Software\Microsoft\'
CommandLine|contains: '\CurrentControlSet\Control\SecurityProviders\WDigest'
CommandLine|contains: '\Microsoft\Windows Defender\'
CommandLine|contains: '\Policies\Microsoft\Windows NT\CurrentVersion\Winlogon'
CommandLine|contains: '\Policies\Microsoft\Windows\OOBE'
CommandLine|contains: '\SOFTWARE\Microsoft\Windows NT\Currentversion\Winlogon'

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	`\AppDataLow\Software\Microsoft\` `\CurrentControlSet\Control\SecurityProviders\WDigest` `\Microsoft\Windows Defender\` `\Policies\Microsoft\Windows NT\CurrentVersion\Winlogon` `\Policies\Microsoft\Windows\OOBE` `\SOFTWARE\Microsoft\Windows NT\Currentversion\Winlogon`
`Image`	ends_with	`\reg.exe` corpus 46 (sigma 46)
`OriginalFileName`	eq	`reg.exe` corpus 29 (sigma 29)