Detection rules › Splunk
Removable Media Detected (Windows Event Log)
Adversaries may move onto systems, possibly those on disconnected or air-gapped networks, by copying malware to removable media and taking advantage of Autorun features when the media is inserted into a system and executes. In the case of Lateral Movement, this may occur through modification of executable files stored on removable media or by copying malware and renaming it to look like a legitimate file to trick users into executing it on a separate system. In the case of Initial Access, this may occur through manual manipulation of the media, modification of systems used to initially format the media, or modification to the media's firmware itself
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Initial Access | T1091 Replication Through Removable Media |
| Lateral Movement | T1091 Replication Through Removable Media |
| Collection | T1025 Data from Removable Media |
References
Event coverage
| Provider | Event | Title |
|---|---|---|
| Security-Auditing | Event ID 6416 | A new external device was recognized by the system. |
Rule body yaml
id: '15702.23323'
title: Removable Media Detected
description: 'Adversaries may move onto systems, possibly those on disconnected or
air-gapped networks, by copying malware to removable media and taking advantage
of Autorun features when the media is inserted into a system and executes. In the
case of Lateral Movement, this may occur through modification of executable files
stored on removable media or by copying malware and renaming it to look like a legitimate
file to trick users into executing it on a separate system. In the case of Initial
Access, this may occur through manual manipulation of the media, modification of
systems used to initially format the media, or modification to the media''s firmware
itself. - Threat Actor Association: APT28, APT29, Camaro Dragon, FIN7, Gamaredon
Group/Shuckworm, UNC4990 - Software Association: Raspberry Robin'
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_winevent` TERM(EventCode=6416) OR "<EventID>6416<"
| rex field=_raw "''DeviceDescription''?>(?<device_description>[^<]+)"| table _time,
host, user, signature_id, process, process_*, parent_process_*, device_description
| bin span=1s | stats values(*) as * by _time, host '
techniques:
- collection:data from removable media
- lateral-movement:replication through removable media
technique_id:
- T1025
- T1091
data_category:
- Windows event logs
references:
- https://threatpost.com/fin7-mailing-malicious-usb-sticks-ransomware/177541/
Stages and Predicates
Stage 1: search
`get_endpoint_data` `get_endpoint_data_winevent` TERM(EventCode=6416) OR "<EventID>6416<"
Stage 2: rex
| rex field=_raw "'DeviceDescription'?>(?<device_description>[^<]+)"
Stage 3: table
| table _time, host, user, signature_id, process, process_*, parent_process_*, device_description
Stage 4: bucket
| bin span=1s
Stage 5: stats
| stats values(*) as * by _time, host
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.
| Field | Kind | Values |
|---|---|---|
EventCode | eq |
|
Search terms
Bare-string tokens in the SPL search body. Splunk matches each token against _raw (the untyped raw event text) anywhere it appears, not against a specific field. These don't surface in the Indicators table because they aren't predicates on a known field.
| Stage | Term |
|---|---|
| 1 | TERM |
| 1 | "<EventID>6416<" |