mirror of
https://github.com/splunk/security_content
synced 2026-06-08 17:32:49 +00:00
Bhavin Patel
87 lines
3.9 KiB
YAML
87 lines
3.9 KiB
YAML
name: Linux Edit Cron Table Parameter
|
|
id: 0d370304-5f26-11ec-a4bb-acde48001122
|
|
version: 1
|
|
date: '2021-12-17'
|
|
author: Teoderick Contreras, Splunk
|
|
status: production
|
|
type: Hunting
|
|
description: 'The following analytic detects the suspicious editing of cron jobs in
|
|
Linux via the crontab command-line parameter. This tactic could be used by adversaries
|
|
or malware to schedule execution of their malicious code, potentially leading to
|
|
system compromise or unauthorized persistent access. It pinpoints this activity
|
|
by monitoring command-line executions involving ''crontab'' and the edit parameter
|
|
(-e).\
|
|
|
|
Recognizing such activity is vital for a SOC as cron job manipulations might signal
|
|
unauthorized persistence attempts or scheduled malicious actions, potentially resulting
|
|
in substantial harm. A true positive signifies an active threat, with implications
|
|
ranging from unauthorized access to broader network compromise.\
|
|
|
|
To implement this analytic, logs capturing process name, parent process, and command-line
|
|
executions from your endpoints must be ingested.\
|
|
|
|
Known false positives could stem from valid administrative tasks or automation processes
|
|
using crontab. To reduce these, fine-tune the filter macros according to the benign
|
|
activities within your environment. These adjustments ensure legitimate actions
|
|
aren''t mistaken for threats, allowing analysts to focus on genuine potential risks.'
|
|
data_source:
|
|
- Sysmon Event ID 1
|
|
search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
|
|
as lastTime from datamodel=Endpoint.Processes where Processes.process_name = crontab
|
|
Processes.process = "*crontab *" Processes.process = "* -e*" 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_edit_cron_table_parameter_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 use this application
|
|
for automation purposes. Please update the filter macros to remove false positives.
|
|
references:
|
|
- https://attack.mitre.org/techniques/T1053/003/
|
|
tags:
|
|
analytic_story:
|
|
- Linux Privilege Escalation
|
|
- Linux Persistence Techniques
|
|
- Linux Living Off The Land
|
|
- Scheduled Tasks
|
|
asset_type: Endpoint
|
|
confidence: 30
|
|
impact: 30
|
|
message: A possible crontab edit command $process$ executed on $dest$
|
|
mitre_attack_id:
|
|
- T1053.003
|
|
- T1053
|
|
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: 9
|
|
security_domain: endpoint
|
|
tests:
|
|
- name: True Positive Test
|
|
attack_data:
|
|
- data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1053.003/crontab_edit_parameter/sysmon_linux.log
|
|
source: Syslog:Linux-Sysmon/Operational
|
|
sourcetype: sysmon_linux
|