splunk_escuAnomaly

Linux Auditd Virtual Disk File And Directory Discovery

The following analytic detects suspicious discovery of virtual disk files and directories, which may indicate an attacker's attempt to locate and access virtualized storage environments. Virtual disks can contain sensitive data or critical system configurations, and unauthorized discovery attempts could signify preparatory actions for data exfiltration or further compromise. By monitoring for unusual or unauthorized searches for virtual disk files and directories, this analytic helps identify potential reconnaissance activities, enabling security teams to respond promptly and safeguard against unauthorized access and data breaches.

MITRE ATT&CK

T1083

Detection Query

`linux_auditd` execve_command IN ("*find*", "*grep*")  AND execve_command IN ("*.vhd*", "*.vhdx*", "*.vmdk*")
  | rename host as dest
  | rename comm as process_name
  | rename exe as process
  | stats count min(_time) as firstTime max(_time) as lastTime
    BY argc execve_command dest
  | `security_content_ctime(firstTime)`
  | `security_content_ctime(lastTime)`
  | `linux_auditd_virtual_disk_file_and_directory_discovery_filter`

Author

Teoderick Contreras, Splunk

Created

2026-03-10

Data Sources

Linux Auditd Execve

References

Tags

Linux Living Off The LandLinux Privilege EscalationLinux Persistence TechniquesCompromised Linux Host

Raw Content

name: Linux Auditd Virtual Disk File And Directory Discovery
id: eec78cef-d4c8-4b35-8f5b-6922102a4a41
version: 8
date: '2026-03-10'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: The following analytic detects suspicious discovery of virtual disk files and directories, which may indicate an attacker's attempt to locate and access virtualized storage environments. Virtual disks can contain sensitive data or critical system configurations, and unauthorized discovery attempts could signify preparatory actions for data exfiltration or further compromise. By monitoring for unusual or unauthorized searches for virtual disk files and directories, this analytic helps identify potential reconnaissance activities, enabling security teams to respond promptly and safeguard against unauthorized access and data breaches.
data_source:
    - Linux Auditd Execve
search: |-
    `linux_auditd` execve_command IN ("*find*", "*grep*")  AND execve_command IN ("*.vhd*", "*.vhdx*", "*.vmdk*")
      | rename host as dest
      | rename comm as process_name
      | rename exe as process
      | stats count min(_time) as firstTime max(_time) as lastTime
        BY argc execve_command dest
      | `security_content_ctime(firstTime)`
      | `security_content_ctime(lastTime)`
      | `linux_auditd_virtual_disk_file_and_directory_discovery_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
    - 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 [$execve_command$] event occurred 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
    asset_type: Endpoint
    mitre_attack_id:
        - T1083
    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/T1083/linux_auditd_find_virtual_disk/auditd_execve_find_vhd.log
          source: auditd
          sourcetype: auditd