Detection rules › Sigma

Potential Privilege Escalation via Local Kerberos Relay over LDAP

Severity
high
Author
Elastic, @SBousseaden
Source
upstream

Detects a suspicious local successful logon event where the Logon Package is Kerberos, the remote address is set to localhost, and the target user SID is the built-in local Administrator account. This may indicate an attempt to leverage a Kerberos relay attack variant that can be used to elevate privilege locally from a domain joined limited user to local System privileges.

MITRE ATT&CK coverage

TacticTechniques
Privilege EscalationT1548 Abuse Elevation Control Mechanism
Defense EvasionT1548 Abuse Elevation Control Mechanism

Event coverage

ProviderEvent IDTitle
Security-Auditing4624An account was successfully logged on.

Stages and Predicates

Stage 1: selection

AuthenticationPackageName: Kerberos
IpAddress: 127.0.0.1
LogonType: 3
TargetUserSid|endswith: -500
TargetUserSid|startswith: S-1-5-21-

Stage 2: not 1 of filter_main_ip_null

IpPort: 0

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.

FieldKindValues
AuthenticationPackageNameeq
  • Kerberos corpus 2 (sigma 1, splunk 1)
IpAddresseq
  • 127.0.0.1 corpus 5 (sigma 5)
IpPorteq
  • 0
LogonTypeeq
  • 3 corpus 12 (splunk 7, sigma 5)
TargetUserSidends_with
  • -500 corpus 2 (sigma 2)
TargetUserSidstarts_with
  • S-1-5-21- corpus 2 (sigma 2)

Neighbors

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.