Detection rules › Splunk

Linux Auditd Clipboard Data Copy

Status
production
Severity
low
Group by
argc, dest, execve_command
Author
Teoderick Contreras, Splunk
Source
github.com/splunk/security_content

The following analytic detects the use of the Linux 'xclip' command to copy data from the clipboard. It leverages Linux Auditd telemetry, focusing on process names and command-line arguments related to clipboard operations. This activity is significant because adversaries can exploit clipboard data to capture sensitive information such as passwords or IP addresses. If confirmed malicious, this technique could lead to unauthorized data exfiltration, compromising sensitive information and potentially aiding further attacks within the environment.

MITRE ATT&CK coverage

TacticTechniques
CollectionT1115 Clipboard Data

Rule body splunk

name: Linux Auditd Clipboard Data Copy
id: 9ddfe470-c4d0-4e60-8668-7337bd699edd
version: 9
creation_date: '2022-06-17'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: The following analytic detects the use of the Linux 'xclip' command to copy data from the clipboard. It leverages Linux Auditd telemetry, focusing on process names and command-line arguments related to clipboard operations. This activity is significant because adversaries can exploit clipboard data to capture sensitive information such as passwords or IP addresses. If confirmed malicious, this technique could lead to unauthorized data exfiltration, compromising sensitive information and potentially aiding further attacks within the environment.
data_source:
    - Linux Auditd Execve
search: |-
    `linux_auditd` execve_command IN ("*xclip*", "*clipboard*") AND execve_command IN ("*-o*", "*-selection *", "*-sel *" )
      | 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_clipboard_data_copy_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: False positives may be present on Linux desktop as it may commonly be used by administrators or end users. Filter as needed.
references:
    - https://attack.mitre.org/techniques/T1115/
    - https://linux.die.net/man/1/xclip
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 [$execve_command$] event occurred on host - [$dest$] to copy data from the clipboard.
analytic_story:
    - Linux Living Off The Land
    - Compromised Linux Host
asset_type: Endpoint
mitre_attack_id:
    - T1115
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/T1115/linux_auditd_xclip/linux_auditd_xclip2.log
          source: auditd
          sourcetype: auditd
      test_type: unit

Stages and Predicates

Stage 1: search

`linux_auditd` execve_command IN ("*xclip*", "*clipboard*") AND execve_command IN ("*-o*", "*-selection *", "*-sel *" )

Stage 2: rename

| rename host as dest

Stage 3: rename

| rename comm as process_name

Stage 4: rename

| rename exe as process

Stage 5: stats

| stats count min(_time) as firstTime max(_time) as lastTime
    BY argc execve_command dest

Stage 6: search

| `security_content_ctime(firstTime)`

Stage 7: search

| `security_content_ctime(lastTime)`

Stage 8: search

| `linux_auditd_clipboard_data_copy_filter`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
execve_commandin
  • "*-o*"
  • "*-sel *"
  • "*-selection *"
  • "*clipboard*"
  • "*xclip*"
sourcetypeeq
  • auditd