Linux File Creation In Init Boot Directory

SPLUNK detection rule by Teoderick Contreras, Splunk · Apache-2.0

The following analytic detects the creation of files in Linux init boot directories, which are used for automatic execution upon system startup. It leverages file system logs to identify new files in directories such as /etc/init.d/ and /etc/rc.d/. This activity is significant as it is a common persistence technique used by adversaries, malware authors, and red teamers. If confirmed malicious, this could allow an attacker to maintain persistence on the compromised host, potentially leading to further exploitation and unauthorized control over the system.

name: Linux File Creation In Init Boot Directory
id: 97d9cfb2-61ad-11ec-bb2d-acde48001122
version: 14
creation_date: '2021-12-23'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: |-
    The following analytic detects the creation of files in Linux init boot directories, which are used for automatic execution upon system startup.
    It leverages file system logs to identify new files in directories such as /etc/init.d/ and /etc/rc.d/. This activity is significant as it is a common persistence technique used by adversaries, malware authors, and red teamers.
    If confirmed malicious, this could allow an attacker to maintain persistence on the compromised host, potentially leading to further exploitation and unauthorized control over the system.
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 = "created"
    Filesystem.file_path IN (
        "*/etc/init.d/*",
        "*/etc/rc.d/*",
        "*/etc/rc.local*",
        "*/sbin/init.d/*"
    )
    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(lastTime)`
    | `security_content_ctime(firstTime)`
    | `linux_file_creation_in_init_boot_directory_filter`
how_to_implement: |-
    To successfully implement this search, you need to be ingesting logs with the file name, file path, and process_guid 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 create file in this folders for automation purposes. Please update the filter macros to remove false positives.
references:
    - https://www.intezer.com/blog/research/kaiji-new-chinese-linux-malware-turning-to-golang/
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"
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 20
          message: A file $file_name$ is created in $file_path$ on $dest$
analytic_story:
    - China-Nexus Threat Activity
    - Backdoor Pingpong
    - Linux Persistence Techniques
    - XorDDos
    - Linux Privilege Escalation
asset_type: Endpoint
mitre_attack_id:
    - T1037.004
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/attack_techniques/T1546.004/linux_init_profile/sysmon_linux.log
          source: Syslog:Linux-Sysmon/Operational
          sourcetype: sysmon:linux
      test_type: unit

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

132546ee-d424-4ccc-86cc-20fca425fed5

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Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

Rejected pattern present

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Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

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