Detection rules › Sigma

Uncommon Outbound Kerberos Connection - Security

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
Credential AccessT1558.003 Steal or Forge Kerberos Tickets: Kerberoasting

Event coverage

ProviderEvent IDTitle
Security-Auditing5156The Windows Filtering Platform has permitted a connection.

Stages and Predicates

Stage 1: selection

DestPort: 88

Stage 2: not 1 of filter_main_lsass

or:
Application|startswith: 'C:'
Application|startswith: '\device\harddiskvolume'
Application|endswith: '\Windows\System32\lsass.exe'

Stage 3: not 1 of filter_optional_*

or:
or:
Application|endswith: '\Program Files (x86)\Google\Chrome\Application\chrome.exe'
Application|endswith: '\Program Files\Google\Chrome\Application\chrome.exe'
or:
Application|startswith: 'C:'
Application|startswith: '\device\harddiskvolume'
or:
Application|endswith: '\Program Files (x86)\Mozilla Firefox\firefox.exe'
Application|endswith: '\Program Files\Mozilla Firefox\firefox.exe'
or:
Application|startswith: 'C:'
Application|startswith: '\device\harddiskvolume'
Application|endswith: '\tomcat\bin\tomcat8.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
Applicationends_with
  • \Program Files (x86)\Google\Chrome\Application\chrome.exe
  • \Program Files (x86)\Mozilla Firefox\firefox.exe
  • \Program Files\Google\Chrome\Application\chrome.exe
  • \Program Files\Mozilla Firefox\firefox.exe
  • \Windows\System32\lsass.exe corpus 2 (sigma 2)
  • \tomcat\bin\tomcat8.exe corpus 2 (sigma 2)
Applicationstarts_with
  • C:
  • \device\harddiskvolume
DestPorteq
  • 88 corpus 3 (sigma 2, splunk 1)

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.