linux_setuid_using_chmod_utility.yml

name: Linux Setuid Using Chmod Utility
id: bf0304b6-6250-11ec-9d7c-acde48001122
version: 1
date: '2021-12-21'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: This analytic looks for suspicious chmod utility execution to enable
  SUID bit. This allows a user to temporarily gain root access, usually in order to
  run a program. For example, only the root account is allowed to change the password
  information contained in the password database; If the SUID bit appears as an s,
  the file's owner also has execute permission to the file; if it appears as an S,
  the file's owner does not have execute permission. The second specialty permission
  is the SGID, or set group id bit. It is similar to the SUID bit, except it can temporarily
  change group membership, usually to execute a program. The SGID bit is set if an
  s or an S appears in the group section of permissions.
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 = chmod
  OR Processes.process = "*chmod *") AND Processes.process IN("* g+s *", "* u+s *",
  "* 4777 *", "* 4577 *") by Processes.dest Processes.user Processes.parent_process_name
  Processes.process_name Processes.process Processes.process_id Processes.parent_process_id
  Processes.process_guid | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)`
  | `security_content_ctime(lastTime)` | `linux_setuid_using_chmod_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: Administrator or network operator can execute this command.
  Please update the filter macros to remove false positives.
references:
- https://www.hackingarticles.in/linux-privilege-escalation-using-capabilities/
tags:
  analytic_story:
  - Linux Privilege Escalation
  - Linux Persistence Techniques
  - Linux Living Off The Land
  asset_type: Endpoint
  confidence: 70
  impact: 70
  message: a commandline $process$ that may set suid or sgid on $dest$
  mitre_attack_id:
  - T1548.001
  - T1548
  observable:
  - name: dest
    type: Hostname
    role:
    - Victim
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  required_fields:
  - _time
  - Processes.dest
  - Processes.user
  - Processes.parent_process_name
  - Processes.process_name
  - Processes.process
  - Processes.process_id
  - Processes.parent_process_id
  risk_score: 49
  security_domain: endpoint
tests:
- name: True Positive Test
  attack_data:
  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1548.001/chmod_uid/sysmon_linux.log
    source: Syslog:Linux-Sysmon/Operational
    sourcetype: sysmon_linux