Windows AppLocker Block Events

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Description

The following analytic utilizes Windows AppLocker event logs to generate risk based on blocks related to AppLocker policy violations. The analytic is designed to identify attempts to bypass application restrictions.

• Type: Anomaly

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

• Last Updated: 2024-03-26
• 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

Search

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

Macros

The SPL above uses the following Macros:

• applocker
• security_content_ctime

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:

• applockereventcodes with data

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

• Windows AppLocker

RBA

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

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

• https://attack.mitre.org/techniques/T1218
• https://learn.microsoft.com/en-us/windows/security/application-security/application-control/windows-defender-application-control/applocker/using-event-viewer-with-applocker
• https://learn.microsoft.com/en-us/windows/security/application-security/application-control/windows-defender-application-control/operations/querying-application-control-events-centrally-using-advanced-hunting

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

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