Detection rules › Splunk
Windows DLL Search Order Hijacking Hunt with Sysmon
The following analytic identifies potential DLL search order hijacking or DLL sideloading by detecting known Windows libraries loaded from non-standard directories. It leverages Sysmon EventCode 7 to monitor DLL loads and cross-references them with a lookup of known hijackable libraries. This activity is significant as it may indicate an attempt to execute malicious code by exploiting DLL search order vulnerabilities. If confirmed malicious, this could allow attackers to gain code execution, escalate privileges, or maintain persistence within the environment.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Persistence | T1574.001 Hijack Execution Flow: DLL |
| Privilege Escalation | T1574.001 Hijack Execution Flow: DLL |
| Defense Evasion | T1574.001 Hijack Execution Flow: DLL |
Event coverage
| Provider | Event ID | Title |
|---|---|---|
| Sysmon | 7 | Image loaded |
Stages and Predicates
Stage 1: search
search NOT process_path IN ("*\\system32\\*", "*\\syswow64\\*", "*\\wbem\\*", "*\\winsxs\\*") EventCode=7
Stage 2: lookup
lookup <lookup> islibrary, library, loaded_file
Stage 3: search
search islibrary=True
Stage 4: stats
stats BY Image, ImageLoaded, dest, loaded_file, loaded_file_path, original_file_name, process_exec, process_guid, process_hash, process_id, process_name, process_path, service_dll_signature_exists, service_dll_signature_verified, signature, signature_id, user_id, vendor_product
Stage 5: search
search
Stage 6: search
search
Stage 7: search
search `macro`
Exclusions
Top-level NOT(...) conjuncts — predicates this rule actively suppresses.
| Stage | Field | Kind | Excluded values |
|---|---|---|---|
| 1 | process_name | in | "*\\system32\\*", "*\\syswow64\\*", "*\\wbem\\*", "*\\winsxs\\*" |
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 |
|
islibrary | eq |
|
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 Remote Access Software BRC4 Loaded Dll (drops 1 filter this rule applies)