Detect RTLO In Process
Description
This search is used to detect the abuse of the right-to-left override (RTLO or RLO) character (U+202E) RTLO. This technique is used by adversaries to disguise a string and/or file name to make it appear benign. The RTLO character is a non-printing Unicode character that causes the text that follows it to be displayed in reverse.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2023-04-26
- Author: Steven Dick
- ID: 22ac27b4-7189-4a4f-9375-b9017c9620d7
Annotations
ATT&CK
Kill Chain Phase
- Exploitation
NIST
- DE.CM
CIS20
- CIS 10
CVE
Search
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| 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`
Macros
The SPL above uses the following Macros:
detect_rtlo_in_process_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Required fields
List of fields required to use this analytic.
- _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
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.
Associated Analytic Story
RBA
Risk Score | Impact | Confidence | Message |
---|---|---|---|
40.0 | 50 | 80 | Suspicious RTLO detected in $process_name$ on endpoint $dest$ by user $user$. |
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
Reference
- 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
Test Dataset
Replay any dataset to Splunk Enterprise by using our replay.py
tool or the UI.
Alternatively you can replay a dataset into a Splunk Attack Range
source | version: 2