splunk_escuAnomaly

Linux Auditd File Permissions Modification Via Chattr

The following analytic detects suspicious file permissions modifications using the chattr command, which may indicate an attacker attempting to manipulate file attributes to evade detection or prevent alteration. The chattr command can be used to make files immutable or restrict deletion, which can be leveraged to protect malicious files or disrupt system operations. By monitoring for unusual or unauthorized chattr usage, this analytic helps identify potential tampering with critical files, enabling security teams to quickly respond to and mitigate threats associated with unauthorized file attribute changes.

MITRE ATT&CK

T1222.002

Detection Query

`linux_auditd` proctitle = "*chattr *" AND proctitle = "* -i*"
  | rename host as dest
  | stats count min(_time) as firstTime max(_time) as lastTime
    BY proctitle dest
  | `security_content_ctime(firstTime)`
  | `security_content_ctime(lastTime)`
  | `linux_auditd_file_permissions_modification_via_chattr_filter`

Author

Teoderick Contreras, Splunk

Created

2026-03-10

Data Sources

Linux Auditd Execve

References

https://www.splunk.com/en_us/blog/security/deep-dive-on-persistence-privilege-escalation-technique-and-detection-in-linux-platform.html

Tags

Linux Living Off The LandLinux Privilege EscalationLinux Persistence TechniquesCompromised Linux Host

Raw Content

name: Linux Auditd File Permissions Modification Via Chattr
id: f2d1110d-b01c-4a58-9975-90a9edeb083a
version: 8
date: '2026-03-10'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: The following analytic detects suspicious file permissions modifications using the chattr command, which may indicate an attacker attempting to manipulate file attributes to evade detection or prevent alteration. The chattr command can be used to make files immutable or restrict deletion, which can be leveraged to protect malicious files or disrupt system operations. By monitoring for unusual or unauthorized chattr usage, this analytic helps identify potential tampering with critical files, enabling security teams to quickly respond to and mitigate threats associated with unauthorized file attribute changes.
data_source:
    - Linux Auditd Execve
search: |-
    `linux_auditd` proctitle = "*chattr *" AND proctitle = "* -i*"
      | rename host as dest
      | stats count min(_time) as firstTime max(_time) as lastTime
        BY proctitle dest
      | `security_content_ctime(firstTime)`
      | `security_content_ctime(lastTime)`
      | `linux_auditd_file_permissions_modification_via_chattr_filter`
how_to_implement: To implement this detection, the process begins by ingesting auditd data, that consists of 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.
references:
    - https://www.splunk.com/en_us/blog/security/deep-dive-on-persistence-privilege-escalation-technique-and-detection-in-linux-platform.html
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 ("$dest$") starthoursago=168  | 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: $info_min_time$
      latest_offset: $info_max_time$
rba:
    message: A [$proctitle$] event occurred on host - [$dest$] to modify file permissions using the "chattr" command.
    risk_objects:
        - field: dest
          type: system
          score: 20
    threat_objects: []
tags:
    analytic_story:
        - Linux Living Off The Land
        - Linux Privilege Escalation
        - Linux Persistence Techniques
        - Compromised Linux Host
    asset_type: Endpoint
    mitre_attack_id:
        - T1222.002
    product:
        - Splunk Enterprise
        - Splunk Enterprise Security
        - Splunk Cloud
    security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1222.002/linux_auditd_chattr_i/auditd_proctitle_chattr.log
          source: auditd
          sourcetype: auditd