Detection rules › Splunk
Windows Access Token Winlogon Duplicate Handle In Uncommon Path
The following analytic detects a process attempting to duplicate the handle of winlogon.exe from an uncommon or public source path. This is identified using Sysmon EventCode 10, focusing on processes targeting winlogon.exe with specific access rights and excluding common system paths. This activity is significant because it may indicate an adversary trying to escalate privileges by leveraging the high-privilege tokens associated with winlogon.exe. If confirmed malicious, this could allow the attacker to gain elevated access, potentially leading to full system compromise and persistent control over the affected host.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Privilege Escalation | T1134.001 Access Token Manipulation: Token Impersonation/Theft |
| Defense Evasion | T1134.001 Access Token Manipulation: Token Impersonation/Theft |
Event coverage
| Provider | Event ID | Title |
|---|---|---|
| Sysmon | 10 | ProcessAccess |
Stages and Predicates
Stage 1: search
search NOT SourceImage IN ("%systemroot%\\*", "C:\\Program File*", "C:\\Windows\\*") EventCode=10 GrantedAccess=0x1040 TargetImage IN ("*\\SysWOW64\\winlogon.exe*", "*\\system32\\winlogon.exe*")
Stage 2: stats
stats BY CallTrace, EventID, GrantedAccess, Guid, Opcode, ProcessID, SecurityID, SourceImage, SourceProcessGUID, SourceProcessId, TargetImage, TargetProcessGUID, TargetProcessId, UserID, dest, granted_access, parent_process_exec, parent_process_guid, parent_process_id, parent_process_name, parent_process_path, process_exec, process_guid, process_id, process_name, process_path, signature, signature_id, user_id, vendor_product
Stage 3: search
search
Stage 4: search
search
Stage 5: search
search `macro`
Exclusions
Top-level NOT(...) conjuncts — predicates this rule actively suppresses.
| Stage | Field | Kind | Excluded values |
|---|---|---|---|
| 1 | Image | in | "%systemroot%\\*", "C:\\Program File*", "C:\\Windows\\*" |
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.
| Field | Kind | Values |
|---|---|---|
EventCode | eq |
|
GrantedAccess | eq |
|
TargetImage | in |
|
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.
- Windows Access Token Manipulation Winlogon Duplicate Token Handle (drops 1 filter this rule applies)