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splunk-security_content/detections/endpoint/linux_at_application_execution.yml
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2023-06-22 16:14:18 -07:00

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YAML

name: Linux At Application Execution
id: bf0a378e-5f3c-11ec-a6de-acde48001122
version: 2
date: '2022-05-26'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: The following analytic detects the execution of the "At" application in Linux, which can be used by attackers to create persistence entries on a compromised host. The "At" application can be used for automation purposes by administrators or network operators, so the filter macros should be updated to remove false positives. If a true positive is found, it suggests an attacker is trying to maintain access to the environment or potentially deliver additional malicious payloads, leading to data theft, ransomware, or other damaging outcomes. To implement this analytic, ensure you are ingesting logs with the required fields from your endpoints into the Endpoint datamodel. When a true positive is detected, it suggests that an attacker is attempting to establish persistence or deliver additional malicious payloads by leveraging the "At" application. This behavior can lead to data theft, ransomware attacks, or other damaging outcomes.\
During triage, the SOC analyst should review the context surrounding the execution of the "At" application. This includes identifying the user, the parent process responsible for invoking the application, and the specific command-line arguments used. It is important to consider whether the execution is expected behavior by an administrator or network operator for legitimate automation purposes.\
The presence of "At" application execution may indicate an attacker's attempt to maintain unauthorized access to the environment. Immediate investigation and response are necessary to mitigate further risks, identify the attacker's intentions, and prevent potential harm to the organization.
data_source:
- Sysmon Event ID 1
search: '| tstats `security_content_summariesonly` count from datamodel=Endpoint.Processes
where Processes.process_name IN ("at", "atd") OR Processes.parent_process_name
IN ("at", "atd") 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_at_application_execution_filter`'
how_to_implement: To successfully implement this search, you need to be ingesting
logs with the process name, parent process, and command-line executions from your
endpoints into the Endpoint datamodel. If you are using Sysmon, you can use the
Add-on for Linux Sysmon from Splunkbase.
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/T1053/001/
- https://www.linkedin.com/pulse/getting-attacker-ip-address-from-malicious-linux-job-craig-rowland/
tags:
analytic_story:
- Linux Privilege Escalation
- Linux Persistence Techniques
- Linux Living Off The Land
- Scheduled Tasks
asset_type: Endpoint
confidence: 30
impact: 30
message: At application was executed in $dest$
mitre_attack_id:
- T1053.002
- 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/T1053.002/at_execution/sysmon_linux.log
source: Syslog:Linux-Sysmon/Operational
sourcetype: sysmon_linux