Detection rules › Splunk

Suspicious WAV file in Appdata Folder

Author
Teoderick Contreras, Splunk
Source
upstream

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.

MITRE ATT&CK coverage

TacticTechniques
CollectionT1113 Screen Capture

Event coverage

ProviderEvent IDTitle
Sysmon1Process creation
Sysmon11FileCreate
Security-Auditing4688A new process has been created.

Stages and Predicates

Stage 1: tstats

tstats WHERE Processes.process_name="*.exe" Processes.process_path="*\\appdata\\Roaming\\*" BY _time, Processes.action, Processes.dest, Processes.original_file_name, Processes.parent_process, Processes.parent_process_exec, Processes.parent_process_guid, Processes.parent_process_id, Processes.parent_process_name, Processes.parent_process_path, Processes.process, Processes.process_exec, Processes.process_guid, Processes.process_hash, Processes.process_id, Processes.process_integrity_level, Processes.process_name, Processes.process_path, Processes.user, Processes.user_id, Processes.vendor_product

Stage 2: search

search

Stage 3: rename

rename

Stage 4: join

join type=inner (...)

Stage 5: search

search `macro`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Filesystem.file_namein
  • "*.wav"
Filesystem.file_patheq
  • "*\\appdata\\Roaming\\*" corpus 2 (splunk 2)
Processes.process_nameeq
  • *.exe corpus 2 (splunk 2)
Processes.process_patheq
  • "*\\appdata\\Roaming\\*" corpus 2 (splunk 2)