ID | Technique | Tactic |
---|---|---|
T1113 | Screen Capture | Collection |
Detection: Suspicious WAV file in Appdata Folder
Description
The following analytic detects the creation of .wav files in the AppData folder, a behavior associated with Remcos RAT malware, which stores audio recordings in this location for data exfiltration. The detection leverages endpoint process and filesystem data to identify .wav file creation within the AppData\Roaming directory. This activity is significant as it indicates potential unauthorized data collection and exfiltration by malware. If confirmed malicious, this could lead to sensitive information being sent to an attacker's command and control server, compromising the affected system's confidentiality.
Search
1
2| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Processes where Processes.process_name=*.exe Processes.process_path="*\\appdata\\Roaming\\*" by _time span=1h Processes.process_id Processes.process_name Processes.process Processes.dest Processes.process_guid
3| `drop_dm_object_name(Processes)`
4|rename process_guid as proc_guid
5| join proc_guid, _time [
6| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Filesystem where Filesystem.file_name IN ("*.wav") Filesystem.file_path = "*\\appdata\\Roaming\\*" by _time span=1h Filesystem.dest Filesystem.file_create_time Filesystem.file_name Filesystem.file_path Filesystem.process_guid
7| `drop_dm_object_name(Filesystem)`
8|rename process_guid as proc_guid
9| fields file_name file_path process_name process_path process dest file_create_time _time proc_guid]
10| `suspicious_wav_file_in_appdata_folder_filter`
Data Source
Name | Platform | Sourcetype | Source | Supported App |
---|---|---|---|---|
CrowdStrike ProcessRollup2 | N/A | 'crowdstrike:events:sensor' |
'crowdstrike' |
N/A |
Macros Used
Name | Value |
---|---|
security_content_summariesonly | summariesonly= summariesonly_config allow_old_summaries= oldsummaries_config fillnull_value= fillnull_config`` |
suspicious_wav_file_in_appdata_folder_filter | search * |
suspicious_wav_file_in_appdata_folder_filter
is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
Default Configuration
This detection is configured by default in Splunk Enterprise Security to run with the following settings:
Setting | Value |
---|---|
Disabled | true |
Cron Schedule | 0 * * * * |
Earliest Time | -70m@m |
Latest Time | -10m@m |
Schedule Window | auto |
Creates Notable | Yes |
Rule Title | %name% |
Rule Description | %description% |
Notable Event Fields | user, dest |
Creates Risk Event | True |
Implementation
To successfully implement this search, you need to be ingesting logs with the process name, parent process, file_name, file_path and command-line executions from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.
Known False Positives
unknown
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
process $process_name$ creating image file $file_path$ in $dest$ | 49 | 70 | 70 |
References
-
https://success.trendmicro.com/dcx/s/solution/1123281-remcos-malware-information?language=en_US
-
https://blog.malwarebytes.com/threat-intelligence/2021/07/remcos-rat-delivered-via-visual-basic/
Detection Testing
Test Type | Status | Dataset | Source | Sourcetype |
---|---|---|---|---|
Validation | ✅ Passing | N/A | N/A | N/A |
Unit | ✅ Passing | Dataset | XmlWinEventLog:Microsoft-Windows-Sysmon/Operational |
xmlwineventlog |
Integration | ✅ Passing | Dataset | XmlWinEventLog:Microsoft-Windows-Sysmon/Operational |
xmlwineventlog |
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: GitHub | Version: 3