Detection rules › Splunk

Linux Deletion Of Services

Status
production
Severity
medium
Group by
CreationUtcTime, computer_name, event_action, file_access_time, file_acl, file_hash, file_modify_time, file_name, file_size, process_guid, process_id, target_filename, user, vendor_product
Author
Teoderick Contreras, Splunk
Source
github.com/splunk/security_content

The following analytic detects the deletion of services on a Linux machine. It leverages filesystem event logs to identify when service files within system directories (e.g., /etc/systemd/, /lib/systemd/, /run/systemd/) are deleted. This activity is significant because attackers may delete or modify services to disable security features or evade defenses. If confirmed malicious, this behavior could indicate an attempt to impair system functionality or execute a destructive payload, potentially leading to system instability or data loss. Immediate investigation is required to determine the responsible process and user.

MITRE ATT&CK coverage

Rule body splunk

name: Linux Deletion Of Services
id: b509bbd3-0331-4aaa-8e4a-d2affe100af6
version: 12
creation_date: '2022-04-12'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: TTP
description: The following analytic detects the deletion of services on a Linux machine. It leverages filesystem event logs to identify when service files within system directories (e.g., /etc/systemd/, /lib/systemd/, /run/systemd/) are deleted. This activity is significant because attackers may delete or modify services to disable security features or evade defenses. If confirmed malicious, this behavior could indicate an attempt to impair system functionality or execute a destructive payload, potentially leading to system instability or data loss. Immediate investigation is required to determine the responsible process and user.
data_source:
    - Sysmon for Linux EventID 11
search: |-
    | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Filesystem
      WHERE Filesystem.action=deleted Filesystem.file_path IN ( "/etc/systemd/*", "*/lib/systemd/*", "*/run/systemd/*") Filesystem.file_path = "*.service"
      BY Filesystem.action Filesystem.dest Filesystem.file_access_time
         Filesystem.file_create_time Filesystem.file_hash Filesystem.file_modify_time
         Filesystem.file_name Filesystem.file_path Filesystem.file_acl
         Filesystem.file_size Filesystem.process_guid Filesystem.process_id
         Filesystem.user Filesystem.vendor_product
    | `drop_dm_object_name(Filesystem)`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `linux_deletion_of_services_filter`
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: Administrator or network operator can execute this command. Please update the filter macros to remove false positives.
references:
    - https://www.sentinelone.com/labs/acidrain-a-modem-wiper-rains-down-on-europe/
    - https://unix.stackexchange.com/questions/224992/where-do-i-put-my-systemd-unit-file
    - https://cert.gov.ua/article/3718487
drilldown_searches:
    - name: View the detection results for - "$dest$"
      search: '%original_detection_search% | search  dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
finding:
    title: A services file $file_name$ deteted on host $dest$ by process GUID -  $process_guid$
    entity:
        field: dest
        type: system
        score: 50
threat_objects:
    - field: file_name
      type: file_name
analytic_story:
    - AwfulShred
    - AcidRain
    - Data Destruction
    - AcidPour
asset_type: Endpoint
mitre_attack_id:
    - T1070.004
    - T1485
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/malware/acidrain/sysmon_linux.log
          source: Syslog:Linux-Sysmon/Operational
          sourcetype: sysmon:linux
      test_type: unit

Stages and Predicates

Stage 1: tstats

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Filesystem
  WHERE Filesystem.action=deleted Filesystem.file_path IN ( "/etc/systemd/*", "*/lib/systemd/*", "*/run/systemd/*") Filesystem.file_path = "*.service"
  BY Filesystem.action Filesystem.dest Filesystem.file_access_time
     Filesystem.file_create_time Filesystem.file_hash Filesystem.file_modify_time
     Filesystem.file_name Filesystem.file_path Filesystem.file_acl
     Filesystem.file_size Filesystem.process_guid Filesystem.process_id
     Filesystem.user Filesystem.vendor_product

Stage 2: search

| `drop_dm_object_name(Filesystem)`

Stage 3: search

| `security_content_ctime(firstTime)`

Stage 4: search

| `security_content_ctime(lastTime)`

Stage 5: search

| `linux_deletion_of_services_filter`

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.

FieldKindValues
Filesystem.actioneq
  • deleted
Filesystem.file_patheq
  • "*.service"
Filesystem.file_pathin
  • "*/lib/systemd/*"
  • "*/run/systemd/*"
  • "/etc/systemd/*"