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Description

The following analytic detects attempts to bypass application restrictions by identifying Windows AppLocker policy violations. It leverages Windows AppLocker event logs, specifically EventCodes 8007, 8004, 8022, 8025, 8029, and 8040, to pinpoint blocked actions. This activity is significant for a SOC as it highlights potential unauthorized application executions, which could indicate malicious intent or policy circumvention. If confirmed malicious, this activity could allow an attacker to execute unauthorized applications, potentially leading to further system compromise or data exfiltration.

  • Type: Anomaly

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2024-05-15
  • Author: Michael Haag, Splunk
  • ID: e369afe8-cd35-47a3-9c1e-d813efc1f7dd

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1218 System Binary Proxy Execution Defense Evasion
Kill Chain Phase
  • Exploitation
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


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`applocker`  EventCode IN (8007, 8004, 8022, 8025, 8029, 8040) 
| spath input=UserData_Xml 
| rename RuleAndFileData.* as *, TargetUser as user, Computer as dest  
| stats count min(_time) as firstTime max(_time) as lastTime by dest, PolicyName, RuleId, user, TargetProcessId, FilePath, FullFilePath, EventCode 
| lookup applockereventcodes EventCode OUTPUT Description 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_applocker_block_events_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_applocker_block_events_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Lookups

The SPL above uses the following Lookups:

Required fields

List of fields required to use this analytic.

  • dest
  • PolicyName
  • RuleId
  • user
  • TargetProcessId
  • FilePath
  • FullFilePath

How To Implement

To implement this analytic, you must be ingesting Windows AppLocker logs into Splunk. Ensure proper logging is setup for AppLocker and data is being ingested into Splunk.

Known False Positives

Administrators may legitimately use AppLocker to allow applications.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
16.0 20 80 An instance of AppLocker policy violation has been detected on $dest$.

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

source | version: 3