Name:Detect mshta renamed id:8f45fcf0-5b68-11eb-ae93-0242ac130002 version:6 date:2024-10-17 author:Michael Haag, Splunk status:production type:Hunting Description:The following analytic identifies instances where mshta.exe has been renamed and executed. It leverages Endpoint Detection and Response (EDR) data, specifically focusing on the original file name field to detect discrepancies. This activity is significant because renaming mshta.exe is a common tactic used by attackers to evade detection and execute malicious scripts. If confirmed malicious, this could allow an attacker to execute arbitrary code, potentially leading to system compromise, data exfiltration, or further lateral movement within the network. Data_source:
-Sysmon EventID 1
-Windows Event Log Security 4688
-CrowdStrike ProcessRollup2
search:| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name!=mshta.exe AND Processes.original_file_name=MSHTA.EXE by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id Processes.original_file_name | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `detect_mshta_renamed_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:Although unlikely, some legitimate applications may use a moved copy of mshta.exe, but never renamed, triggering a false positive. References: -https://github.com/redcanaryco/AtomicTestHarnesses -https://redcanary.com/blog/introducing-atomictestharnesses/ drilldown_searches:
: tags: analytic_story: - 'Suspicious MSHTA Activity' - 'Living Off The Land' asset_type:Endpoint confidence:100 impact:80 message:The following $process_name$ has been identified as renamed, spawning from $parent_process_name$ on $dest$ executed by user $user$ mitre_attack_id: - 'T1218' - 'T1218.005' observable: name:'user' type:'User' - role: - 'Victim' name:'dest' type:'Hostname' - role: - 'Victim' name:'parent_process_name' type:'Process' - role: - 'Attacker' name:'process_name' type:'Process' - role: - 'Attacker' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - '_time' - 'Processes.dest' - 'Processes.user' - 'Processes.parent_process_name' - 'Processes.parent_process' - 'Processes.original_file_name' - 'Processes.process_name' - 'Processes.process' - 'Processes.process_id' - 'Processes.parent_process_path' - 'Processes.process_path' - 'Processes.parent_process_id' risk_score:80 security_domain:endpoint
