splunk_escuAnomaly

Linux Auditd Whoami User Discovery

The following analytic detects the suspicious use of the whoami command, which may indicate an attacker trying to gather information about the current user account on a compromised system. The whoami command is commonly used to verify user privileges and identity, especially during initial stages of an attack to assess the level of access. By monitoring for unusual or unauthorized executions of whoami, this analytic helps in identifying potential reconnaissance activities, enabling security teams to take action before the attacker escalates privileges or conducts further malicious operations.

MITRE ATT&CK

T1033

Detection Query

`linux_auditd` type=SYSCALL comm=whoami OR exe= "*/whoami"
  | rename host as dest
  | stats count min(_time) as firstTime max(_time) as lastTime
    BY comm exe syscall
       uid ppid pid
       dest success
  | `security_content_ctime(firstTime)`
  | `security_content_ctime(lastTime)`
  | `linux_auditd_whoami_user_discovery_filter`

Author

Teoderick Contreras, Splunk

Created

2026-03-12

Data Sources

Linux Auditd Syscall

References

Tags

Linux Living Off The LandLinux Privilege EscalationLinux Persistence TechniquesCompromised Linux HostQuietVault

Raw Content

name: Linux Auditd Whoami User Discovery
id: d1ff2e22-310d-446a-80b3-faedaa7b3b52
version: 7
date: '2026-03-12'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: The following analytic detects the suspicious use of the whoami command, which may indicate an attacker trying to gather information about the current user account on a compromised system. The whoami command is commonly used to verify user privileges and identity, especially during initial stages of an attack to assess the level of access. By monitoring for unusual or unauthorized executions of whoami, this analytic helps in identifying potential reconnaissance activities, enabling security teams to take action before the attacker escalates privileges or conducts further malicious operations.
data_source:
    - Linux Auditd Syscall
search: |-
    `linux_auditd` type=SYSCALL comm=whoami OR exe= "*/whoami"
      | rename host as dest
      | stats count min(_time) as firstTime max(_time) as lastTime
        BY comm exe syscall
           uid ppid pid
           dest success
      | `security_content_ctime(firstTime)`
      | `security_content_ctime(lastTime)`
      | `linux_auditd_whoami_user_discovery_filter`
how_to_implement: To implement this detection, the process begins by ingesting auditd data, that consist 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
    - https://github.com/peass-ng/PEASS-ng/tree/master/linPEAS
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 SYSCALL - [$comm$] event was executed on host - [$dest$] to discover virtual disk files and directories.
    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
        - QuietVault
    asset_type: Endpoint
    mitre_attack_id:
        - T1033
    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/T1033/linux_auditd_whoami_new/linux_auditd_new_whoami.log
          source: auditd
          sourcetype: auditd