Detection: Linux Auditd Shred Overwrite Command

Updated Date: 2026-05-13 ID: ce2bde4d-a1d4-4452-8c87-98440e5adfb3 Author: Teoderick Contreras, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the execution of the 'shred' command on a Linux machine, which is used to overwrite files to make them unrecoverable. It leverages data from Linux Auditd, focusing on process names and command-line arguments. This activity is significant because the 'shred' command can be used in destructive attacks, such as those seen in the Industroyer2 malware targeting energy facilities. If confirmed malicious, this activity could lead to the permanent destruction of critical files, severely impacting system integrity and data availability.

Search

 1`linux_auditd`  proctitle IN ("*shred*")  AND proctitle IN ("*-n*", "*-z*", "*-u*", "*-s*")
 2  
 3| rename host as dest
 4  
 5| stats count min(_time) as firstTime max(_time) as lastTime
 6    BY proctitle dest
 7  
 8| `security_content_ctime(firstTime)`
 9  
10| `security_content_ctime(lastTime)`
11  
12| `linux_auditd_shred_overwrite_command_filter`

Data Source

Name	Platform	Sourcetype	Source
Linux Auditd Proctitle	Linux	`'auditd'`	`'auditd'`

Macros Used

Name	Value
security_content_ctime	`convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)`
linux_auditd_shred_overwrite_command_filter	`search *`

linux_auditd_shred_overwrite_command_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1485	Data Destruction	Impact

Actions on Objectives

DE.CM

CIS 10

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Finding (Notable)	Yes
Rule Title	`%name%`
Rule Description	`%description%`
Notable Event Fields	user, dest
Creates Intermediate Finding (Risk Event)	No

TTP detections generate a Finding (Notable) and may generate Intermediate Findings (Risk Events) for associated entities.

Implementation

To implement this detection, the process begins by ingesting auditd data, that consist SYSCALL, TYPE, EXECVE and PROCTITLE events, which captures command-line executions and process details on Unix/Linux systems. These logs should be ingested and processed using Splunk Add-on for Unix and Linux (https://splunkbase.splunk.com/app/833), which is essential for correctly parsing and categorizing the data. The next step involves normalizing the field names to match the field names set by the Splunk Common Information Model (CIM) to ensure consistency across different data sources and enhance the efficiency of data modeling. This approach enables effective monitoring and detection of linux endpoints where auditd is deployed

Known False Positives

Administrator or network operator can use this application for automation purposes. Please update the filter macros to remove false positives.

Associated Analytic Story

Finding

Title	Entity Field	Entity Type	Risk Score
A [$proctitle$] event occurred on host - [$dest$] to overwrite files using the shred utility.	dest	system	50

References

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`auditd`	`auditd`
Integration	✅ Passing	Dataset	`auditd`	`auditd`

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: GitHub | Version: 9