Name:Linux Deleting Critical Directory Using RM Command id:33f89303-cc6f-49ad-921d-2eaea38a6f7a version:3 date:2024-09-30 author:Teoderick Contreras, Splunk status:production type:TTP Description:The following analytic detects the deletion of critical directories on a Linux machine using the `rm` command with argument rf. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on command-line executions targeting directories like /boot, /var/log, /etc, and /dev. This activity is significant because deleting these directories can severely disrupt system operations and is often associated with destructive campaigns like Industroyer2. If confirmed malicious, this action could lead to system instability, data loss, and potential downtime, making it crucial for immediate investigation and response. Data_source:
-Sysmon for Linux EventID 1
search:| 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= "* -rf *" AND Processes.process IN ("*/boot/*", "*/var/log/*", "*/etc/*", "*/dev/*") by Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id Processes.process_guid Processes.dest Processes.user | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `linux_deleting_critical_directory_using_rm_command_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://www.welivesecurity.com/2022/04/12/industroyer2-industroyer-reloaded/ -https://cert.gov.ua/article/39518 drilldown_searches: name:'View the detection results for - "$dest$"' search:'%original_detection_search% | search dest = "$dest$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$dest$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") starthoursago=168 | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' tags: analytic_story: - 'AwfulShred' - 'Data Destruction' - 'Industroyer2' asset_type:Endpoint confidence:80 impact:80 message:A deletion in known critical list of folder using rm command $process$ executed on $dest$ mitre_attack_id: - 'T1485' 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:64 security_domain:endpoint
