Detection rules › Sigma

Uncommon Outbound Kerberos Connection

Severity
medium
Author
Ilyas Ochkov, oscd.community
Source
upstream

Detects uncommon outbound network activity via Kerberos default port indicating possible lateral movement or first stage PrivEsc via delegation.

MITRE ATT&CK coverage

TacticTechniques
Defense EvasionT1550.003 Use Alternate Authentication Material: Pass the Ticket
Credential AccessT1558 Steal or Forge Kerberos Tickets
Lateral MovementT1550.003 Use Alternate Authentication Material: Pass the Ticket

Event coverage

ProviderEvent IDTitle
Sysmon3Network connection

Stages and Predicates

Stage 1: selection

DestinationPort: 88
Initiated: true

Stage 2: not 1 of filter_main_lsass

Image: 'C:\Windows\System32\lsass.exe'

Stage 3: not 1 of filter_optional_*

or:
Image|endswith: '\tomcat\bin\tomcat8.exe'
Image: 'C:\Program Files (x86)\Google\Chrome\Application\chrome.exe'
Image: 'C:\Program Files (x86)\Mozilla Firefox\firefox.exe'
Image: 'C:\Program Files\Google\Chrome\Application\chrome.exe'
Image: 'C:\Program Files\Mozilla Firefox\firefox.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.

FieldKindValues
DestinationPorteq
  • 88 corpus 3 (sigma 2, splunk 1)
Imageends_with
  • \tomcat\bin\tomcat8.exe corpus 2 (sigma 2)
Imageeq
  • C:\Program Files (x86)\Google\Chrome\Application\chrome.exe corpus 11 (sigma 11)
  • C:\Program Files (x86)\Mozilla Firefox\firefox.exe corpus 11 (sigma 11)
  • C:\Program Files\Google\Chrome\Application\chrome.exe corpus 12 (sigma 12)
  • C:\Program Files\Mozilla Firefox\firefox.exe corpus 12 (sigma 12)
  • C:\Windows\System32\lsass.exe
Initiatedeq
  • true corpus 40 (sigma 40)