Detection rules › Splunk

SAM Database File Access Attempt

Author
Michael Haag, Mauricio Velazco, Splunk
Source
upstream

The following analytic detects attempts to access the SAM, SYSTEM, or SECURITY database files within the windows\system32\config directory using Windows Security EventCode 4663. This detection leverages Windows Security Event logs to identify unauthorized access attempts. Monitoring this activity is crucial as it indicates potential credential access attempts, possibly exploiting vulnerabilities like CVE-2021-36934. If confirmed malicious, an attacker could extract user passwords, leading to unauthorized access, privilege escalation, and further compromise of the system.

MITRE ATT&CK coverage

TacticTechniques
Credential AccessT1003.002 OS Credential Dumping: Security Account Manager

Event coverage

ProviderEvent IDTitle
Security-Auditing4663An attempt was made to access an object.

Stages and Predicates

Stage 1: search

search EventCode=4663 ObjectName IN ("*\\Windows\\System32\\config\\SAM*", "*\\Windows\\System32\\config\\SECURITY*", "*\\Windows\\System32\\config\\SYSTEM*") ProcessName!="*\\\\dllhost.exe"

Stage 2: stats

stats BY ProcessName, ObjectName, dest, src_user

Stage 3: rename

rename

Stage 4: search

search `macro`

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
EventCodeeq
  • 4663 corpus 16 (splunk 16)
ObjectNamein
  • "*\\Windows\\System32\\config\\SAM*"
  • "*\\Windows\\System32\\config\\SECURITY*"
  • "*\\Windows\\System32\\config\\SYSTEM*"
ProcessNamene
  • *\\dllhost.exe

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.