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Description

The following analytic detects a process loading a version.dll file from a directory other than %windir%\system32 or %windir%\syswow64. This detection leverages Sysmon EventCode 7 to identify instances where an unsigned or improperly located version.dll is loaded. This activity is significant as it is a common technique used in ransomware and APT malware campaigns, including Brute Ratel C4, to execute malicious code via DLL side loading. If confirmed malicious, this could allow attackers to execute arbitrary code, maintain persistence, and potentially compromise the target host.

  • Type: Anomaly

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2024-05-15
  • Author: Teoderick Contreras, Splunk
  • ID: 8351340b-ac0e-41ec-8b07-dd01bf32d6ea

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1574.001 DLL Search Order Hijacking Persistence, Privilege Escalation, Defense Evasion
T1574 Hijack Execution Flow Persistence, Privilege Escalation, Defense Evasion
Kill Chain Phase
  • Installation
  • Exploitation
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


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`sysmon` EventCode=7 ImageLoaded = "*\\version.dll" AND (Signed = "false" OR NOT(ImageLoaded IN("*\\windows\\system32*",  "*\\windows\\syswow64\\*"))) 
| stats count min(_time) as firstTime max(_time) as lastTime by Image ImageLoaded process_name dest EventCode Signed ProcessId 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_hijack_execution_flow_version_dll_side_load_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_hijack_execution_flow_version_dll_side_load_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _time
  • Image
  • ImageLoaded
  • process_name
  • dest
  • EventCode
  • Signed
  • ProcessId

How To Implement

The latest Sysmon TA 3.0 https://splunkbase.splunk.com/app/5709 will add the ImageLoaded name to the process_name field, allowing this query to work. Use as an example and implement for other products.

Known False Positives

unknown

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
35.0 50 70 a process $Image$ loading $ImageLoaded$ as a side load dll in $dest$

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

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

source | version: 2