Uncommon Service Installation Image Path

Severity: medium
Author: Florian Roth (Nextron Systems)
Source: upstream

Detects uncommon service installation commands by looking at suspicious or uncommon image path values containing references to encoded powershell commands, temporary paths, etc.

MITRE ATT&CK coverage

Tactic	Techniques
Persistence	`T1543.003` Create or Modify System Process: Windows Service
Privilege Escalation	`T1543.003` Create or Modify System Process: Windows Service

Event coverage

Provider	Event ID	Title
Service-Control-Manager	7045

Stages and Predicates

Stage 1: `selection`

Provider_Name: 'Service Control Manager'

Stage 2: `suspicious_paths`

or:
ImagePath|contains: '\Users\Public\'
ImagePath|contains: '\Windows\Temp\'
ImagePath|contains: '\\\\.\\pipe'

Stage 3: `all of suspicious_encoded_flag`

ImagePath|contains: ' -e'

Stage 4: `all of suspicious_encoded_keywords`

or:
ImagePath|contains: ' IAB'
ImagePath|contains: ' JAB'
ImagePath|contains: ' PAA'
ImagePath|contains: ' SQBFAFgA'
ImagePath|contains: ' SUVYI'
ImagePath|contains: ' aQBlAHgA'
ImagePath|contains: ' aWV4I'

Stage 5: `not 1 of filter_main_defender_def_updates`

ImagePath|startswith: 'C:\ProgramData\Microsoft\Windows Defender\Definition Updates\'

Stage 6: `not 1 of filter_optional_thor_remote`

ImagePath|startswith: 'C:\WINDOWS\TEMP\thor10-remote\thor64.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
`ImagePath`	match	`-e` `IAB` `JAB` `PAA` `SQBFAFgA` `SUVYI` `aQBlAHgA` `aWV4I` `\Users\Public\` `\Windows\Temp\` `\\\\.\\pipe`
`ImagePath`	starts_with	`C:\ProgramData\Microsoft\Windows Defender\Definition Updates\` `C:\WINDOWS\TEMP\thor10-remote\thor64.exe`
`Provider_Name`	eq	`Service Control Manager` corpus 43 (sigma 43)

Neighbors

Stricter alternatives (narrower than this rule)

The rules below may be useful if you find the current rule is too noisy / lacks specificity.

Invoke-Obfuscation Via Use Rundll32 - System [sigma] (adds 5 filters) (first-stage match only; downstream stages may differ)
Invoke-Obfuscation VAR++ LAUNCHER OBFUSCATION - System [sigma] (adds 5 filters) (first-stage match only; downstream stages may differ)
Invoke-Obfuscation VAR+ Launcher - System [sigma] (adds 4 filters) (first-stage match only; downstream stages may differ)
Invoke-Obfuscation COMPRESS OBFUSCATION - System [sigma] (adds 4 filters) (first-stage match only; downstream stages may differ)
Invoke-Obfuscation RUNDLL LAUNCHER - System [sigma] (adds 4 filters) (first-stage match only; downstream stages may differ)
Invoke-Obfuscation CLIP+ Launcher - System [sigma] (adds 3 filters) (first-stage match only; downstream stages may differ)
Invoke-Obfuscation STDIN+ Launcher - System [sigma] (adds 3 filters) (first-stage match only; downstream stages may differ)
Invoke-Obfuscation Via Stdin - System [sigma] (adds 3 filters) (first-stage match only; downstream stages may differ)
Invoke-Obfuscation Via Use MSHTA - System [sigma] (adds 2 filters) (first-stage match only; downstream stages may differ)
ProcessHacker Privilege Elevation [sigma] (adds 2 filters) (first-stage match only; downstream stages may differ)
Invoke-Obfuscation Via Use Clip - System [sigma] (adds 1 filter) (first-stage match only; downstream stages may differ)
Credential Dumping Tools Service Execution - System [sigma] (adds 1 filter) (first-stage match only; downstream stages may differ)
Moriya Rootkit - System [sigma] (adds 1 filter) (first-stage match only; downstream stages may differ)
PowerShell Scripts Installed as Services [sigma] (adds 1 filter) (first-stage match only; downstream stages may differ)
Service Installed By Unusual Client - System [sigma] (adds 1 filter) (first-stage match only; downstream stages may differ)
Suspicious Service Installation [sigma] (adds 1 filter) (first-stage match only; downstream stages may differ)
Tap Driver Installation [sigma] (adds 1 filter) (first-stage match only; downstream stages may differ)
RTCore Suspicious Service Installation [sigma] (adds 1 filter) (first-stage match only; downstream stages may differ)
Service Installation in Suspicious Folder [sigma] (adds 1 filter) (first-stage match only; downstream stages may differ)

Broader alternatives (more inclusive than this rule)

These rules match a superset of what this rule catches. They cover the same events plus more. Use them if you want wider coverage and can absorb more false positives.

Invoke-Obfuscation Obfuscated IEX Invocation - System [sigma] (drops 1 filter this rule applies) (first-stage match only; downstream stages may differ)