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Windows Privilege Escalation User Process Spawn System Process

Author
Steven Dick
Source
upstream

The following analytic detects when a process with low, medium, or high integrity spawns a system integrity process from a user-controlled location. This behavior is indicative of privilege escalation attempts where attackers elevate their privileges to SYSTEM level from a user-controlled process or service. The detection leverages Sysmon data, specifically Event ID 15, to identify such transitions. Monitoring this activity is crucial as it can signify an attacker gaining SYSTEM-level access, potentially leading to full control over the affected system, unauthorized access to sensitive data, and further malicious activities.

MITRE ATT&CK coverage

TacticTechniques
Privilege EscalationT1068 Exploitation for Privilege Escalation, T1134 Access Token Manipulation, T1548 Abuse Elevation Control Mechanism
Defense EvasionT1134 Access Token Manipulation, T1548 Abuse Elevation Control Mechanism

Event coverage

ProviderEvent IDTitle
Sysmon1Process creation

Stages and Predicates

Stage 1: tstats

tstats WHERE NOT Processes.user IN ("*$", "*LOCAL SERVICE", "*NETWORK SERVICE", "*SYSTEM", "DWM-*") Processes.process_integrity_level IN ("high", "low", "medium") Processes.process_path IN ("*\\ProgramData\\*", "*\\Temp\\*", "*\\Users\\*", "*\\\\*") BY Processes.action, Processes.dest, Processes.original_file_name, Processes.parent_process, Processes.parent_process_exec, Processes.parent_process_guid, Processes.parent_process_id, Processes.parent_process_name, Processes.parent_process_path, Processes.process, Processes.process_exec, Processes.process_guid, Processes.process_hash, Processes.process_id, Processes.process_integrity_level, Processes.process_name, Processes.process_path, Processes.user, Processes.user_id, Processes.vendor_product

Stage 2: search

search

Stage 3: eval

eval ... using (process_guid)

Stage 4: join

join type=inner (...)

Stage 5: fields

fields count, dest, firstTime, lastTime, parent_process, parent_process_guid, parent_process_name, process, process_current_directory, process_guid, process_integrity_level, process_name, process_path, system_process, system_process_current_directory, system_process_integrity_level, system_process_name, system_process_path, system_user, user

Stage 6: search

search

Stage 7: search

search

Stage 8: search

search `macro`

Exclusions

Top-level NOT(...) conjuncts — predicates this rule actively suppresses.

StageFieldKindExcluded values
1userin"*$", "*LOCAL SERVICE", "*NETWORK SERVICE", "*SYSTEM", "DWM-*"

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
Processes.parent_process_pathin
  • "*\\ProgramData\\*" corpus 2 (splunk 2)
  • "*\\Temp\\*" corpus 2 (splunk 2)
  • "*\\Users\\*" corpus 2 (splunk 2)
  • "*\\\\*" corpus 2 (splunk 2)
Processes.process_integrity_leveleq
  • "system" corpus 2 (splunk 2)
Processes.process_integrity_levelin
  • "high" corpus 2 (splunk 2)
  • "low" corpus 3 (splunk 3)
  • "medium" corpus 3 (splunk 3)
Processes.process_pathin
  • "*\\ProgramData\\*" corpus 3 (splunk 3)
  • "*\\Temp\\*" corpus 3 (splunk 3)
  • "*\\Users\\*" corpus 2 (splunk 2)
  • "*\\\\*" corpus 2 (splunk 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.