This analytic looks for suspicious linux processes that delete service unit configuration files. This technique was seen in several malware to delete service configuration files to corrupt a services or security product as part of its defense evasion. This TTP detection can be a good indicator of possible malware try to kill several services or a wiper like AwfulShred shell script that wipes the targeted linux host
- Type: Anomaly
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2023-04-14
- Author: Teoderick Contreras, Splunk
- ID: 6c077f81-2a83-4537-afbc-0e62e3215d55
Kill Chain Phase
- CIS 10
1 2 3 4 5 | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name = "rm" AND Processes.process = "*rm *" AND Processes.process = "*.service" 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)` | `linux_indicator_removal_service_file_deletion_filter`
The SPL above uses the following Macros:
linux_indicator_removal_service_file_deletion_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
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
network admin can delete services unit configuration file as part of normal software installation. Filter is needed.
Associated Analytic Story
|36.0||60||60||a $process_name$ has a commandline $process$ to delete service configuration file 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.
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