Linux Shell History Access Via Command Line Utility

SPLUNK detection rule by Raven Tait, Splunk · Apache-2.0

The following analytic detects attempts to read shell history files (bash, zsh, fish, etc.). A history file is a log file that records all the commands executed in a shell on a Linux or Unix-based operating system. A malicious actor who gains access to a user's shell history file can potentially obtain sensitive information and use it to compromise the user's system and data.

name: Linux Shell History Access Via Command Line Utility
id: 0e4c2544-b27a-4a2d-b9be-cac8efe515fb
version: 1
creation_date: '2026-07-08'
modification_date: '2026-07-08'
author: Raven Tait, Splunk
status: production
type: Anomaly
description: |-
    The following analytic detects attempts to read shell history files (bash, zsh, fish, etc.).
    A history file is a log file that records all the commands executed in a shell on a Linux or Unix-based operating system.
    A malicious actor who gains access to a user's shell history file can potentially obtain sensitive information and use it to compromise the user's system and data.
data_source:
    - Sysmon for Linux EventID 1
search: |-
    | tstats `security_content_summariesonly`
      count min(_time) as firstTime
            max(_time) as lastTime

    from datamodel=Endpoint.Processes where

    Processes.process_name IN (
        "cat",
        "fmt",
        "head",
        "less",
        "more",
        "nano",
        "sort",
        "tail",
        "uniq",
        "vi",
        "vim"
    )
    Processes.process IN (
        "*.bash_history*",
        "*.history*",
        "*.sh_history*",
        "*.zhistory*",
        "*.zsh_history*",
        "*fish_history*"
    )

    by Processes.process Processes.vendor_product Processes.user_id Processes.process_hash
       Processes.parent_process_name Processes.parent_process_exec Processes.action Processes.dest
       Processes.process_current_directory Processes.process_path Processes.process_integrity_level
       Processes.original_file_name Processes.parent_process Processes.parent_process_path
       Processes.parent_process_guid Processes.parent_process_id Processes.process_guid
       Processes.process_id Processes.user Processes.process_name

    | `drop_dm_object_name(Processes)`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `linux_shell_history_access_via_command_line_utility_filter`
how_to_implement: |-
    The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint` data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
known_false_positives: |-
    Legitimate system administrators and automated scripts may access shell history files for auditing or troubleshooting purposes. Filter based on known administrative accounts and approved tooling in your environment.
drilldown_searches:
    - earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
      name: View the detection results for - "$user$" and "$dest$"
      search: '%original_detection_search% | search  user = "$user$" dest = "$dest$"'
    - name: View risk events for the last 7 days for - "$user$" and "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$", "$dest$") | 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: Potential shell history access [$process$] by [$user$] on [$dest$] via [$process_name$].
        - field: user
          type: user
          score: 20
          message: Potential shell history access [$process$] by [$user$] on [$dest$] via [$process_name$].
threat_objects:
    - field: process_name
      type: process_name
analytic_story:
    - Linux Post-Exploitation
    - Compromised Linux Host
    - Linux Privilege Escalation
    - Linux Persistence Techniques
    - Credential Dumping
asset_type: Endpoint
mitre_attack_id:
    - T1552.003
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      test_type: unit
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1552.003/linux_bash_history_access/snapattack_linux.log
          source: Syslog:Linux-Sysmon/Operational
          sourcetype: sysmon:linux

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