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splunk-security_content/detections/endpoint/linux_php_privilege_escalation.yml
2024-08-15 15:36:03 -05:00

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YAML

name: Linux PHP Privilege Escalation
id: 4fc4c031-e5be-4cc0-8cf9-49f9f507bcb5
version: 3
date: '2024-08-14'
author: Gowthamaraj Rajendran, Splunk
status: production
type: Anomaly
description: The following analytic detects the execution of PHP commands with elevated
privileges on a Linux system. It identifies instances where PHP is used in conjunction
with 'sudo' and 'system' commands, indicating an attempt to run system commands
as the root user. This detection leverages data from Endpoint Detection and Response
(EDR) agents, focusing on process command-line arguments. This activity is significant
because it can indicate an attempt to escalate privileges, potentially leading to
full root access. If confirmed malicious, this could allow an attacker to execute
arbitrary commands with root privileges, compromising the entire system.
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="*php*-r*"
AND Processes.process="*system*" AND Processes.process="*sudo*" 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_php_privilege_escalation_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: False positives may be present, filter as needed.
references:
- https://gtfobins.github.io/gtfobins/php/
- https://en.wikipedia.org/wiki/PHP
tags:
analytic_story:
- Linux Privilege Escalation
- Linux Living Off The Land
asset_type: Endpoint
confidence: 50
impact: 60
message: An instance of $parent_process_name$ spawning $process_name$ was identified
on endpoint $dest$
mitre_attack_id:
- T1548.003
- T1548
observable:
- name: dest
type: Hostname
role:
- Victim
- name: parent_process_name
type: Process
role:
- Attacker
- name: process_name
type: Process
role:
- Attacker
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: 30
security_domain: endpoint
tests:
- name: True Positive Test
attack_data:
- data:
https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1548/php/sysmon_linux.log
source: Syslog:Linux-Sysmon/Operational
sourcetype: sysmon:linux
update_timestamp: true