Name:Excessive Usage Of Taskkill id:fe5bca48-accb-11eb-a67c-acde48001122 version:4 date:2024-09-30 author:Teoderick Contreras, Splunk status:production type:Anomaly Description:The following analytic identifies excessive usage of `taskkill.exe`, a command-line utility used to terminate processes. The detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on instances where `taskkill.exe` is executed ten or more times within a one-minute span. This behavior is significant as adversaries often use `taskkill.exe` to disable security tools or other critical processes to evade detection. If confirmed malicious, this activity could allow attackers to bypass security defenses, maintain persistence, and further compromise the system. Data_source:
-Sysmon EventID 1
-Windows Event Log Security 4688
-CrowdStrike ProcessRollup2
search:| tstats `security_content_summariesonly` values(Processes.process) as process values(Processes.process_id) as process_id count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name = "taskkill.exe" by Processes.parent_process_name Processes.process_name Processes.dest Processes.user _time span=1m | where count >=10 | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `excessive_usage_of_taskkill_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:Unknown. Filter as needed. References: -https://thedfirreport.com/2020/04/20/sqlserver-or-the-miner-in-the-basement/ -https://www.joesandbox.com/analysis/702680/0/html 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: - 'XMRig' - 'Azorult' - 'CISA AA22-264A' - 'AgentTesla' - 'CISA AA22-277A' - 'NjRAT' asset_type:Endpoint confidence:70 impact:40 message:Excessive usage of taskkill.exe with process id $process_id$ (more than 10 within 1m) has been detected on $dest$ with a parent process of $parent_process_name$. mitre_attack_id: - 'T1562.001' - 'T1562' observable: name:'dest' type:'Endpoint' - role: - 'Victim' name:'parent_process_name' type:'Process Name' - role: - 'Attacker' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - '_time' - 'Processes.parent_process_name' - 'Processes.process_name' - 'Processes.dest' - 'Processes.user' - 'Processes.process' - 'Processes.process_id' risk_score:28 security_domain:endpoint
