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Description

This search is to detect a suspicious rundll32.exe process having a http connection and do a dns query in some web domain. This technique was seen in IcedID malware where the rundll32 that execute its payload will contact amazon.com to check internet connect and to communicate to its C&C server to download config and other file component.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2021-07-26
  • Author: Teoderick Contreras, Splunk
  • ID: f1483f5e-ee29-11eb-9d23-acde48001122

ATT&CK

ID Technique Tactic
T1218.011 Rundll32 Defense Evasion
`sysmon` EventCode=22 process_name="rundll32.exe" 
| stats count min(_time) as firstTime max(_time) as lastTime by Image QueryName QueryStatus ProcessId direction Computer 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `rundll32_dnsquery_filter`

Associated Analytic Story

How To Implement

To successfully implement this search, you need to be ingesting logs with the process name and eventcode = 22 dnsquery executions from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA. Tune and filter known instances where renamed rundll32.exe may be used.

Required field

  • _time
  • Image
  • QueryName
  • QueryStatus
  • ProcessId
  • direction
  • Computer

Kill Chain Phase

  • Exploitation

Known False Positives

unknown

RBA

Risk Score Impact Confidence Message
56.0 70 80 rundll32 process $process_name$ having a dns query to $QueryName$ 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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