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Description

This analytic identifies the suspicious Remote Thread execution of rundll32.exe process to "firefox.exe" and "chrome.exe" browser. This technique was seen in IcedID malware where it hooks the browser to parse banking information as user used the targetted browser process.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2021-07-26
  • Author: Teoderick Contreras, Splunk
  • ID: f8a22586-ee2d-11eb-a193-acde48001122

ATT&CK

ID Technique Tactic
T1055 Process Injection Defense Evasion, Privilege Escalation
`sysmon` EventCode=8 SourceImage = "*\\rundll32.exe" TargetImage IN ("*\\firefox.exe", "*\\chrome.exe", "*\\iexplore.exe","*\\microsoftedgecp.exe") 
| stats count min(_time) as firstTime max(_time) as lastTime by SourceImage TargetImage TargetProcessId SourceProcessId StartAddress EventCode Computer 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `rundll32_createremotethread_in_browser_filter`

Associated Analytic Story

How To Implement

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.

Required field

  • _time
  • SourceImage
  • TargetImage
  • TargetProcessId
  • SourceProcessId
  • StartAddress
  • EventCode
  • Computer

Kill Chain Phase

  • Exploitation

Known False Positives

unknown

RBA

Risk Score Impact Confidence Message
70.0 70 100 rundl32 process $SourceImage$ create a remote thread to browser process $TargetImage$ in host $Computer$

Reference

Test Dataset

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

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