Name:Suspicious msbuild path id:f5198224-551c-11eb-ae93-0242ac130002 version:5 date:2024-09-30 author:Michael Haag, Splunk status:production type:TTP Description:The following analytic detects the execution of msbuild.exe from a non-standard path. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process execution logs that deviate from typical msbuild.exe locations. This activity is significant because msbuild.exe is commonly abused by attackers to execute malicious code, and running it from an unusual path can indicate an attempt to evade detection. If confirmed malicious, this behavior could allow an attacker to execute arbitrary code, potentially leading to system compromise and further malicious activities. Data_source:
-Sysmon EventID 1
-Windows Event Log Security 4688
-CrowdStrike ProcessRollup2
search:| tstats `security_content_summariesonly` count values(Processes.process_name) as process_name values(Processes.process) as process min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_msbuild` AND (Processes.process_path!=*\\framework*\\v*\\*) by Processes.dest Processes.original_file_name Processes.parent_process Processes.user | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`| `suspicious_msbuild_path_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:Some legitimate applications may use a moved copy of msbuild.exe, triggering a false positive. Baselining of MSBuild.exe usage is recommended to better understand it's path usage. Visual Studio runs an instance out of a path that will need to be filtered on. References: -https://lolbas-project.github.io/lolbas/Binaries/Msbuild/ -https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1127.001/T1127.001.md drilldown_searches: name:'View the detection results for - "$dest$" and "$user$"' search:'%original_detection_search% | search dest = "$dest$" user = "$user$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$dest$" and "$user$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$", "$user$") 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: - 'Trusted Developer Utilities Proxy Execution MSBuild' - 'Masquerading - Rename System Utilities' - 'Living Off The Land' - 'Cobalt Strike' - 'BlackByte Ransomware' - 'Graceful Wipe Out Attack' asset_type:Endpoint confidence:70 impact:70 message:Msbuild.exe ran from an uncommon path on $dest$ execyted by $user$ mitre_attack_id: - 'T1036' - 'T1127' - 'T1036.003' - 'T1127.001' observable: name:'dest' type:'Endpoint' - role: - 'Victim' name:'user' type:'User' - role: - 'Victim' 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:49 security_domain:endpoint
