Detection rules › Sigma

Creation Of Non-Existent System DLL

Status
test
Severity
medium
Log source
product windows, category file_event
Author
Nasreddine Bencherchali (Nextron Systems), fornotes
Source
github.com/SigmaHQ/sigma

Detects creation of specific system DLL files that are usually not present on the system (or at least not in system directories) but may be loaded by legitimate processes. Phantom DLL hijacking involves placing malicious DLLs with names of non-existent system binaries in locations where legitimate applications may search for them, leading to execution of the malicious DLLs. Thus, the creation of such DLLs may indicate preparation for phantom DLL hijacking attacks.

MITRE ATT&CK coverage

Event coverage

ProviderEventTitle
SysmonEvent ID 11FileCreate

Rule body yaml

title: Creation Of Non-Existent System DLL
id: df6ecb8b-7822-4f4b-b412-08f524b4576c
related:
    - id: 6b98b92b-4f00-4f62-b4fe-4d1920215771 # ImageLoad rule
      type: similar
status: test
description: |
    Detects creation of specific system DLL files that are  usually not present on the system (or at least not in system directories) but may be loaded by legitimate processes.
    Phantom DLL hijacking involves placing malicious DLLs with names of non-existent system binaries in locations where legitimate applications may search for them, leading to execution of the malicious DLLs.
    Thus, the creation of such DLLs may indicate preparation for phantom DLL hijacking attacks.
references:
    - http://remoteawesomethoughts.blogspot.com/2019/05/windows-10-task-schedulerservice.html
    - https://clement.notin.org/blog/2020/09/12/CVE-2020-7315-McAfee-Agent-DLL-injection/
    - https://decoded.avast.io/martinchlumecky/png-steganography/
    - https://github.com/blackarrowsec/redteam-research/tree/26e6fc0c0d30d364758fa11c2922064a9a7fd309/LPE%20via%20StorSvc
    - https://github.com/Wh04m1001/SysmonEoP
    - https://itm4n.github.io/cdpsvc-dll-hijacking/
    - https://posts.specterops.io/lateral-movement-scm-and-dll-hijacking-primer-d2f61e8ab992
    - https://securelist.com/passiveneuron-campaign-with-apt-implants-and-cobalt-strike/117745/
    - https://www.crowdstrike.com/en-us/blog/4-ways-adversaries-hijack-dlls/
    - https://www.hexacorn.com/blog/2013/12/08/beyond-good-ol-run-key-part-5/
    - https://www.hexacorn.com/blog/2025/06/14/wermgr-exe-boot-offdmpsvc-dll-lolbin/
    - https://www.hexacorn.com/blog/2025/06/14/wpr-exe-boottrace-phantom-dll-axeonoffhelper-dll-lolbin/
    - https://x.com/0gtweet/status/1564131230941122561
author: Nasreddine Bencherchali (Nextron Systems), fornotes
date: 2022-12-01
modified: 2026-01-24
tags:
    - attack.persistence
    - attack.privilege-escalation
    - attack.execution
    - attack.stealth
    - attack.t1574.001
logsource:
    product: windows
    category: file_event
detection:
    selection:
        TargetFilename|endswith:
            - ':\Windows\System32\axeonoffhelper.dll'
            - ':\Windows\System32\cdpsgshims.dll'
            - ':\Windows\System32\oci.dll'
            - ':\Windows\System32\offdmpsvc.dll'
            - ':\Windows\System32\shellchromeapi.dll'
            - ':\Windows\System32\TSMSISrv.dll'
            - ':\Windows\System32\TSVIPSrv.dll'
            - ':\Windows\System32\wbem\wbemcomn.dll'
            - ':\Windows\System32\WLBSCTRL.dll'
            - ':\Windows\System32\wow64log.dll'
            - ':\Windows\System32\WptsExtensions.dll'
            - '\SprintCSP.dll'
    condition: selection
falsepositives:
    - Unknown
level: medium
regression_tests_path: regression_data/rules/windows/file/file_event/file_event_win_create_non_existent_dlls/info.yml

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    TargetFilename|endswith:
        - ':\Windows\System32\axeonoffhelper.dll'
        - ':\Windows\System32\cdpsgshims.dll'
        - ':\Windows\System32\oci.dll'
        - ':\Windows\System32\offdmpsvc.dll'
        - ':\Windows\System32\shellchromeapi.dll'
        - ':\Windows\System32\TSMSISrv.dll'
        - ':\Windows\System32\TSVIPSrv.dll'
        - ':\Windows\System32\wbem\wbemcomn.dll'
        - ':\Windows\System32\WLBSCTRL.dll'
        - ':\Windows\System32\wow64log.dll'
        - ':\Windows\System32\WptsExtensions.dll'
        - '\SprintCSP.dll'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
TargetFilenameends_with
  • :\Windows\System32\TSMSISrv.dll
  • :\Windows\System32\TSVIPSrv.dll
  • :\Windows\System32\WLBSCTRL.dll
  • :\Windows\System32\WptsExtensions.dll
  • :\Windows\System32\axeonoffhelper.dll
  • :\Windows\System32\cdpsgshims.dll
  • :\Windows\System32\oci.dll
  • :\Windows\System32\offdmpsvc.dll
  • :\Windows\System32\shellchromeapi.dll
  • :\Windows\System32\wbem\wbemcomn.dll
  • :\Windows\System32\wow64log.dll
  • \SprintCSP.dll