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Description

This analytic looks for suspicious linux processes that delete service unit configuration files. This technique was seen in several malware to delete service configuration files to corrupt a services or security product as part of its defense evasion. This TTP detection can be a good indicator of possible malware try to kill several services or a wiper like AwfulShred shell script that wipes the targeted linux host

  • Type: Anomaly
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2023-02-08
  • Author: Teoderick Contreras, Splunk
  • ID: 6c077f81-2a83-4537-afbc-0e62e3215d55

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1070.004 File Deletion Defense Evasion
T1070 Indicator Removal Defense Evasion
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 3
  • CIS 5
  • CIS 16
CVE 


1
2
3
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5



| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name = "rm"  AND Processes.process = "*rm *"  AND Processes.process = "*.service" by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id Processes.process_guid 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `linux_indicator_removal_service_file_deletion_filter`

Macros

The SPL above uses the following Macros:

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

Required fields

List of fields required to use this analytic.

  • _time
  • Processes.dest
  • Processes.user
  • Processes.parent_process_name
  • Processes.process_name
  • Processes.process
  • Processes.process_id
  • Processes.parent_process_id

How To Implement

To successfully implement this search, you need to be ingesting logs with the process name, parent process, and command-line executions from your endpoints. If you are using Sysmon, you can use the Add-on for Linux Sysmon from Splunkbase.

Known False Positives

network admin can delete services unit configuration file as part of normal software installation. Filter is needed.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
36.0 60 60 a $process_name$ has a commandline $process$ to delete service configuration file in $dest$

: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

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