Detection: Windows Process Injection Of Wermgr to Known Browser

Updated Date: 2024-05-21 ID: aec755a5-3a2c-4be0-ab34-6540e68644e9 Author: Teoderick Contreras, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic identifies the suspicious remote thread execution of the wermgr.exe process into known browsers such as firefox.exe, chrome.exe, and others. It leverages Sysmon EventCode 8 logs to detect this behavior by monitoring SourceImage and TargetImage fields. This activity is significant because it is indicative of Qakbot malware, which injects malicious code into legitimate processes to steal information. If confirmed malicious, this activity could allow attackers to execute arbitrary code, escalate privileges, and exfiltrate sensitive data from the compromised host.

1`sysmon` EventCode=8 SourceImage = "*\\wermgr.exe" TargetImage IN ("*\\firefox.exe", "*\\chrome.exe", "*\\iexplore.exe","*\\microsoftedgecp.exe") 
2| stats count min(_time) as firstTime max(_time) as lastTime by SourceImage TargetImage SourceProcessGuid SourceProcessId StartAddress StartFunction TargetProcessGuid TargetProcessId  EventCode dest 
3| `security_content_ctime(firstTime)` 
4| `security_content_ctime(lastTime)` 
5| `windows_process_injection_of_wermgr_to_known_browser_filter`

Data Source

Name Platform Sourcetype Source Supported App
Sysmon EventID 8 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($field$)
windows_process_injection_of_wermgr_to_known_browser_filter search *
windows_process_injection_of_wermgr_to_known_browser_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
T1055.001 Dynamic-link Library Injection Defense Evasion
T1055 Process Injection Privilege Escalation
KillChainPhase.EXPLOITAITON
NistCategory.DE_CM
Cis18Value.CIS_10
BackdoorDiplomacy
Lazarus Group
Leviathan
Malteiro
Putter Panda
TA505
Tropic Trooper
Turla
Wizard Spider
APT32
APT37
APT41
APT5
Cobalt Group
Kimsuky
PLATINUM
Silence
TA2541
Turla
Wizard Spider

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 SourceImage, TargetImage, and EventCode executions from your endpoints related to create remote thread or injecting codes. 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
wermgr.exe process $SourceImage$ create a remote thread to a browser process $TargetImage$ in host $dest$ 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: 2