Detection: Windows Known Abused DLL Loaded Suspiciously

Updated Date: 2024-11-13 ID: dd6d1f16-adc0-4e87-9c34-06189516b803 Author: Steven Dick Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects when DLLs with known abuse history are loaded from an unusual location. This activity may represent an attacker performing a DLL search order or sideload hijacking technique. These techniques are used to gain persistence as well as elevate privileges on the target system. This detection relies on Sysmon EID7 and is compatible with all Officla Sysmon TA versions.

Search

 1`sysmon` ImageLoaded EventCode=7 NOT ImageLoaded IN ("*\\Program Files*","*\\system32\\*", "*\\syswow64\\*","*\\winsxs\\*","*\\wbem\\*") 
 2| stats latest(ProcessGuid) as process_guid, count, min(_time) as firstTime, max(_time) as lastTime by User, Computer, Image, ImageLoaded 
 3| rename User as user, Computer as dest, Image as process, ImageLoaded as loaded_file 
 4| eval process_name = case(isnotnull(process),replace(process,"(.*\\\)(?=.*(\.\w*)$
 5|(\w+)$)","")), loaded_file_path = case(isnotnull(loaded_file), replace(loaded_file, "(:[\w\. ]+)", "")), loaded_file = case(isnotnull(loaded_file),replace(loaded_file,"(.*\\\)(?=.*(\.\w*)$
 6|(\w+)$)","")), user = case(NOT user IN ("-"), replace(user, "(.*)\\\(.+)$","\2")) 
 7| lookup hijacklibs_loaded library AS loaded_file OUTPUT islibrary comment as desc 
 8| lookup hijacklibs_loaded library AS loaded_file excludes as loaded_file_path OUTPUT islibrary as excluded 
 9| search islibrary = TRUE AND excluded = false 
10| stats values(*) as * by dest, process_name, process, process_guid, loaded_file, loaded_file_path 
11| `security_content_ctime(firstTime)` 
12| `security_content_ctime(lastTime)` 
13| `windows_known_abused_dll_loaded_suspiciously_filter`

Data Source

Name	Platform	Sourcetype	Source
Sysmon EventID 7	Windows	`'xmlwineventlog'`	`'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'`

Macros Used

Name	Value
security_content_ctime	`convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)`
windows_known_abused_dll_loaded_suspiciously_filter	`search *`

windows_known_abused_dll_loaded_suspiciously_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
T1574.001	DLL Search Order Hijacking	Defense Evasion
T1574.002	DLL Side-Loading	Persistence
T1574	Hijack Execution Flow	Privilege Escalation

Exploitation

Installation

DE.CM

CIS 10

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

The following analytic requires Sysmon operational logs to be imported, with EID7 being mapped to the process_name field. Modify the sysmon macro as needed to match the sourcetype or add index.

Known False Positives

DLLs being loaded by user mode programs for legitimate reasons.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

The module [$loaded_file$] was loaded from an unusual location by [$process$]

Risk Object	Risk Object Type	Risk Score	Threat Objects
dest	system	10	process
user	user	10	process

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