This analytic looks for suspicious process kworker commandline in a linux machine. kworker process name or thread are common names of kernel threads in linux process. This hunting detections can lead to investigate process contains process path in writable directory in linux like /home/, /var/log and /tmp/. This technique was seen in cyclopsblink malware to blend its core and other of its child process as normal kworker on the compromised machine. This detection might be a good pivot to look for other IOC related to cyclopsblink malware or attacks.
- Type: Hunting
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2022-04-30
- Author: Teoderick Contreras, Splunk
- ID: 1cefb270-74a5-4e27-aa0c-2b6fa7c5b4ed
Kill Chain Phase
- CIS 3
- CIS 5
- CIS 16
1 2 3 4 5 6 | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.parent_process = "*[kworker/*" Processes.parent_process_path IN ("/home/*", "/tmp/*", "/var/log/*") Processes.process="*iptables*" by Processes.parent_process_name Processes.parent_process Processes.process_name Processes.process Processes.process_id Processes.parent_process_id Processes.parent_process_path Processes.process_guid Processes.dest Processes.user | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `linux_kworker_process_in_writable_process_path_filter`
The SPL above uses the following Macros:
linux_kworker_process_in_writable_process_path_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
List of fields required to use this analytic.
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. If you are using Sysmon, you can use the Add-on for Linux Sysmon from Splunkbase.
Known False Positives
Associated Analytic Story
|36.0||60||60||a $process_name$ with kworker commandline in $dest$|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
source | version: 2