Detection rules › Splunk
Windows RunMRU Registry Key or Value Deleted
The following analytic detects the deletion or modification of Most Recently Used (MRU) command entries stored within the Windows Registry. Adversaries often clear these registry keys, such as HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\RunMRU, to remove forensic evidence of commands executed via the Windows Run dialog or other system utilities. This activity aims to obscure their actions, hinder incident response efforts, and evade detection. Detection focuses on monitoring for changes (deletion of values or modification of the MRUList value) to these specific registry paths, particularly when performed by unusual processes or outside of typical user behavior. Anomalous deletion events can indicate an attempt at defense evasion or post-exploitation cleanup by a malicious actor.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Persistence | T1112 Modify Registry |
| Defense Evasion | T1112 Modify Registry |
Event coverage
| Provider | Event ID | Title |
|---|---|---|
| Sysmon | 12 | RegistryEvent (Object create and delete) |
Stages and Predicates
Stage 1: tstats
tstats WHERE Registry.action="deleted" Registry.registry_path="*\\Software\\Microsoft\\Windows\\CurrentVersion\\Explorer\\RunMRU*" BY Registry.action, Registry.dest, Registry.process_guid, Registry.process_id, Registry.registry_hive, Registry.registry_path, Registry.registry_key_name, Registry.registry_value_data, Registry.registry_value_name, Registry.registry_value_type, Registry.status, Registry.user, Registry.vendor_product
Stage 2: search
search
Stage 3: search
search
Stage 4: search
search
Stage 5: 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.
| Field | Kind | Values |
|---|---|---|
Registry.action | eq |
|
Registry.registry_path | eq |
|