Detection: Windows Unsigned DLL Side-Loading In Same Process Path

Updated Date: 2024-06-07 ID: 3cf85c02-f9d6-4186-bf3c-e70ee99fbc7f Author: Teoderick Contreras, Splunk Type: TTP Product: Splunk Enterprise Security

Description

This detection identifies unsigned DLLs loaded through DLL side-loading with same file path with the process loaded the DLL, a technique observed in DarkGate malware. This detection monitors DLL loading, verifies signatures, and flags unsigned DLLs. Suspicious file paths and known executable associations are checked. Detecting such suspicious DLLs is crucial in preventing privilege escalation attacks and other potential security breaches. Regular security assessments, thorough monitoring, and implementing security best practices are essential in safeguarding systems from such threats.

Search

1`sysmon` EventCode=7 Signed=false SignatureStatus != Valid NOT (Image IN ("*:\\windows\\system32\\*", "*:\\windows\\syswow64\\*", "c:\\Program Files*")) NOT (ImageLoaded IN ("*:\\windows\\system32\\*", "*:\\windows\\syswow64\\*", "c:\\Program Files*")) 
2|  rex field=Image "(?<ImageFolderPath>.+\\\)" 
3|  rex field=ImageLoaded "(?<ImageLoadedFolderPath>.+\\\)" 
4|  where ImageFolderPath = ImageLoadedFolderPath 
5| stats count min(_time) as firstTime max(_time) as lastTime by Image ProcessGuid ImageLoaded user Computer EventCode ImageFolderPath ImageLoadedFolderPath Company Description Product Signed SignatureStatus 
6|  rename Computer as dest 
7| `security_content_ctime(firstTime)` 
8| `security_content_ctime(lastTime)` 
9| `windows_unsigned_dll_side_loading_in_same_process_path_filter`

Data Source

Name	Platform	Sourcetype	Source	Supported App
Sysmon EventID 7	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($field$)`
windows_unsigned_dll_side_loading_in_same_process_path_filter	`search *`

windows_unsigned_dll_side_loading_in_same_process_path_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
T1574.002	DLL Side-Loading	Defense Evasion
T1574	Hijack Execution Flow	Persistence

KillChainPhase.EXPLOITAITON

KillChainPhase.INSTALLATION

NistCategory.DE_CM

Cis18Value.CIS_10

APT19

APT3

APT32

APT41

BRONZE BUTLER

BlackTech

Chimera

Cinnamon Tempest

Earth Lusca

FIN13

GALLIUM

Higaisa

Lazarus Group

LuminousMoth

MuddyWater

Mustang Panda

Naikon

Patchwork

SideCopy

Sidewinder

Threat Group-3390

Tropic Trooper

menuPass

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 logs with the process name and imageloaded 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
An unsigned dll module was loaded on $dest$	49	70	70

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: 1