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splunk-security_content/detections/endpoint/linux_ssh_authorized_keys_modification.yml
Michael Haag 55bc63720d auth key
2022-07-27 15:30:48 -06:00

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3.0 KiB
YAML

name: Linux SSH Authorized Keys Modification
id: f5ab595e-28e5-4327-8077-5008ba97c850
version: 1
date: '2022-07-27'
author: Michael Haag, Splunk
type: Anomaly
datamodel:
- Endpoint
description: The following analytic identifies based on process execution the modification of SSH Authorized Keys. Adversaries perform this behavior to persist on endpoints.
During triage, review parallel processes and capture any additional file modifications for review.
search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
as lastTime from datamodel=Endpoint.Processes where Processes.process_name IN ("bash","cat") Processes.process IN ("*/authorized_keys*")
by Processes.dest Processes.user Processes.parent_process_name Processes.process_name
Processes.process Processes.process_id Processes.parent_process_id
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `linux_ssh_authorized_keys_modification_filter`'
how_to_implement: To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the `Endpoint` datamodel in the `Processes` node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.
known_false_positives: Filtering will be required as system administrators will add and remove. One way to filter query is to add "echo".
references:
- https://redcanary.com/blog/lateral-movement-with-secure-shell/
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1098.004/T1098.004.md
tags:
analytic_story:
- Linux Living Off The Land
asset_type: Endpoint
cis20:
- CIS 3
- CIS 5
- CIS 16
confidence: 50
context:
- Source:Endpoint
- Stage:Persistence
dataset:
- https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1098.004/ssh_authorized_keys/authkey_linux-sysmon.log
impact: 30
kill_chain_phases:
- Installation
message: An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest$ by user $user$ modifying SSH Authorized Keys.
mitre_attack_id:
- T1098.004
nist:
- DE.CM
observable:
- name: user
type: User
role:
- Victim
- name: dest
type: Hostname
role:
- Victim
- name: parent_process_name
type: Process
role:
- Parent Process
- name: process_name
type: Process
role:
- Child Process
product:
- Splunk Enterprise
- Splunk Enterprise Security
- Splunk Cloud
required_fields:
- _time
- Processes.dest
- Processes.user
- Processes.parent_process_name #parent process name
- Processes.parent_process #parent cmdline
- Processes.original_file_name
- Processes.process_name #process name
- Processes.process #process cmdline
- Processes.process_id
- Processes.parent_process_path
- Processes.process_path
- Processes.parent_process_id
risk_score: 15
security_domain: endpoint