Name:Detect RTLO In Process id:22ac27b4-7189-4a4f-9375-b9017c9620d7 version:4 date:2024-09-30 author:Steven Dick status:production type:TTP Description:The following analytic identifies the abuse of the right-to-left override (RTLO) character (U+202E) in process names. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process execution logs and command-line data. This activity is significant because adversaries use the RTLO character to disguise malicious files or commands, making them appear benign. If confirmed malicious, this technique can allow attackers to execute harmful code undetected, potentially leading to unauthorized access, data exfiltration, or further system compromise. 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!=unknown AND Processes.action=allowed by Processes.dest Processes.user Processes.original_file_name Processes.parent_process_name Processes.parent_process Processes.process_name Processes.process Processes.process_id Processes.process_guid Processes.parent_process_id | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `drop_dm_object_name(Processes)` | regex process="\\x{202E}" | rex field=process "(?<RTLO_command_1>.+)(?<RTLO_exist_process>\\x{202E})(?<RTLO_command_2>.+)" | eval process_with_RTLO=process | eval process=RTLO_command_1.RTLO_command_2 | fields - RTLO* | `detect_rtlo_in_process_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:Implementation in regions that use right to left in native language. References: -https://attack.mitre.org/techniques/T1036/002/ -https://resources.infosecinstitute.com/topic/spoof-using-right-to-left-override-rtlo-technique-2/ -https://www.trendmicro.com/en_us/research/17/f/following-trail-blacktech-cyber-espionage-campaigns.html drilldown_searches: name:'View the detection results for - "$user$" and "$dest$"' search:'%original_detection_search% | search user = "$user$" dest = "$dest$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$user$" and "$dest$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$", "$dest$") 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: - 'Spearphishing Attachments' asset_type:Endpoint confidence:80 impact:50 message:Suspicious RTLO detected in $process_name$ on endpoint $dest$ by user $user$. mitre_attack_id: - 'T1036.002' - 'T1036' observable: name:'user' type:'User' - role: - 'Victim' name:'dest' type:'Endpoint' - role: - 'Victim' name:'process_name' type:'Process Name' - role: - 'Attacker' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - '_time' - 'Processes.dest' - 'Processes.user' - 'Processes.original_file_name' - 'Processes.process_name' - 'Processes.process' - 'Processes.process_id' - 'Processes.process_guid' - 'Processes.parent_process_id' - 'Processes.parent_process_name' - 'Processes.parent_process' risk_score:40 security_domain:endpoint
