Detection: Detect SharpHound File Modifications

Description

The following analytic detects the creation of files typically associated with SharpHound, a reconnaissance tool used for gathering domain and trust data. It leverages file modification events from the Endpoint.Filesystem data model, focusing on default file naming patterns like *_BloodHound.zip and various JSON files. This activity is significant as it indicates potential domain enumeration, which is a precursor to more targeted attacks. If confirmed malicious, an attacker could gain detailed insights into the domain structure, facilitating lateral movement and privilege escalation.

1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Filesystem where Filesystem.file_name IN ("*bloodhound.zip", "*_computers.json", "*_gpos.json", "*_domains.json", "*_users.json", "*_groups.json", "*_ous.json", "*_containers.json") by Filesystem.file_create_time Filesystem.process_id  Filesystem.file_name Filesystem.file_path Filesystem.dest Filesystem.user
3| `drop_dm_object_name(Filesystem)` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `detect_sharphound_file_modifications_filter`

Data Source

Name Platform Sourcetype Source Supported App
Sysmon EventID 11 Windows icon Windows 'xmlwineventlog' 'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational' N/A

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
detect_sharphound_file_modifications_filter search *
detect_sharphound_file_modifications_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1087.002 Domain Account Discovery
T1069.001 Local Groups Discovery
T1482 Domain Trust Discovery Discovery
T1087.001 Local Account Discovery
T1087 Account Discovery Discovery
T1069.002 Domain Groups Discovery
T1069 Permission Groups Discovery Discovery
KillChainPhase.EXPLOITAITON
NistCategory.DE_CM
Cis18Value.CIS_10
APT41
BRONZE BUTLER
Chimera
Dragonfly
FIN13
FIN6
Fox Kitten
Ke3chang
LAPSUS$
MuddyWater
OilRig
Poseidon Group
Sandworm Team
Scattered Spider
ToddyCat
Turla
Volt Typhoon
Wizard Spider
menuPass
Chimera
HEXANE
OilRig
Tonto Team
Turla
Volt Typhoon
admin@338
Akira
Chimera
Earth Lusca
FIN8
Magic Hound
APT1
APT3
APT32
APT41
Chimera
Fox Kitten
Ke3chang
Moses Staff
OilRig
Poseidon Group
Threat Group-3390
Turla
admin@338
FIN13
Dragonfly
FIN7
Inception
Ke3chang
LAPSUS$
OilRig
ToddyCat
Turla
Volt Typhoon
APT3
APT41
FIN13
TA505

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
This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

To successfully implement this search you need to be ingesting information on file modifications that include the name of the process, and file, responsible for the changes from your endpoints into the Endpoint datamodel in the Filesystem node.

Known False Positives

False positives should be limited as the analytic is specific to a filename with extension .zip. Filter as needed.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
Potential SharpHound file modifications identified on $dest$ 24 30 80
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

References

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: 4