Detection rules › Sigma
Medium risk local/domain local group membership change
Detects scenarios where a suspicious group membership is changed.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Persistence | T1098 Account Manipulation |
Event coverage
| Provider | Event | Title |
|---|---|---|
| Security-Auditing | Event ID 4732 | A member was added to a security-enabled local group. |
Rule body yaml
title: Medium risk local/domain local group membership change
description: Detects scenarios where a suspicious group membership is changed.
references:
- https://github.com/mdecrevoisier/EVTX-to-MITRE-Attack/tree/master/TA0003-Persistence/T1098.xxx-Account%20manipulation
- https://ss64.com/nt/syntax-groups.html
- https://docs.microsoft.com/en-us/windows/security/identity-protection/access-control/security-identifiers
tags:
- attack.persistence
- attack.t1098
author: mdecrevoisier
status: experimental
logsource:
product: windows
service: security
detection:
selection:
EventID: 4732 # local and domain local group
TargetSid|startswith: 'S-1-5-32'
TargetSid|endswith:
- '-546' # Guests
- '-550' # Print Operators
- '-555' # Remote Desktop Users
- '-556' # Network Configuration Operators
- '-557' # Incoming Forest Trust Builders
- '-560' # Windows Authorization Access Group
- '-562' # Distributed COM Users
- '-568' # IIS_IUSRS
- '-569' # Cryptographic Operators
- '-573' # Event Log Readers
- '-574' # Certificate Service DCOM Access
- '-579' # Access Control Assistance Operators
- '-580' # Remote Management Users
- '-582' # Storage Replica Administrators
# add DnsAdmins group but has no default RID
filter_sytem:
SubjectUserSid: 'S-1-5-18' # LAPS or others IAM solutions may trigger this as a false positive
filter_iis:
TargetSid: "S-1-5-32-568" # IIS_IUSRS
MemberSid: "S-1-5-20" # Network service account
condition: selection and not (filter_sytem OR filter_iis)
falsepositives:
- Administrator activity
level: high
Stages and Predicates
Stage 0: condition
selection and not (filter_sytem OR filter_iis)Stage 1: selection
selection:
EventID: 4732
TargetSid|startswith: 'S-1-5-32'
TargetSid|endswith:
- '-546'
- '-550'
- '-555'
- '-556'
- '-557'
- '-560'
- '-562'
- '-568'
- '-569'
- '-573'
- '-574'
- '-579'
- '-580'
- '-582'
Stage 2: not filter_sytem
filter_sytem:
SubjectUserSid: 'S-1-5-18'
Stage 3: not filter_iis
filter_iis:
TargetSid: "S-1-5-32-568"
MemberSid: "S-1-5-20"
Exclusions
Top-level NOT(...) conjuncts: predicates this rule actively suppresses.
| Field | Kind | Excluded values |
|---|---|---|
SubjectUserSid | eq | S-1-5-18 |
MemberSid | eq | S-1-5-20 |
TargetSid | eq | S-1-5-32-568 |
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.