Sigma rule: Potentially Suspicious Rundll32 Activity

Rule

Title

Potentially Suspicious Rundll32 Activity

Status

test

Level

medium

Author

juju4, Jonhnathan Ribeiro, oscd.community, Nasreddine Bencherchali (Nextron Systems)

Date

2019-01-16

Modified

2023-05-17

File

rules/windows/process_creation/proc_creation_win_rundll32_susp_activity.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects suspicious execution of rundll32, with specific calls to some DLLs with known LOLBIN functionalities

Log source

product

windows

category

process_creation

Detection

selection:
    - CommandLine|contains|all:
          - 'javascript:'
          - '.RegisterXLL'
    - CommandLine|contains|all:
          - 'url.dll'
          - 'OpenURL'
    - CommandLine|contains|all:
          - 'url.dll'
          - 'OpenURLA'
    - CommandLine|contains|all:
          - 'url.dll'
          - 'FileProtocolHandler'
    - CommandLine|contains|all:
          - 'zipfldr.dll'
          - 'RouteTheCall'
    - CommandLine|contains|all:
          - 'shell32.dll'
          - 'Control_RunDLL'
    - CommandLine|contains|all:
          - 'shell32.dll'
          - 'ShellExec_RunDLL'
    - CommandLine|contains|all:
          - 'mshtml.dll'
          - 'PrintHTML'
    - CommandLine|contains|all:
          - 'advpack.dll'
          - 'LaunchINFSection'
    - CommandLine|contains|all:
          - 'advpack.dll'
          - 'RegisterOCX'
    - CommandLine|contains|all:
          - 'ieadvpack.dll'
          - 'LaunchINFSection'
    - CommandLine|contains|all:
          - 'ieadvpack.dll'
          - 'RegisterOCX'
    - CommandLine|contains|all:
          - 'ieframe.dll'
          - 'OpenURL'
    - CommandLine|contains|all:
          - 'shdocvw.dll'
          - 'OpenURL'
    - CommandLine|contains|all:
          - 'syssetup.dll'
          - 'SetupInfObjectInstallAction'
    - CommandLine|contains|all:
          - 'setupapi.dll'
          - 'InstallHinfSection'
    - CommandLine|contains|all:
          - 'pcwutl.dll'
          - 'LaunchApplication'
    - CommandLine|contains|all:
          - 'dfshim.dll'
          - 'ShOpenVerbApplication'
    - CommandLine|contains|all:
          - 'dfshim.dll'
          - 'ShOpenVerbShortcut'
    - CommandLine|contains|all:
          - 'scrobj.dll'
          - 'GenerateTypeLib'
          - 'http'
    - CommandLine|contains|all:
          - 'shimgvw.dll'
          - 'ImageView_Fullscreen'
          - 'http'
    - CommandLine|contains|all:
          - 'comsvcs.dll'
          - 'MiniDump'
filter_main_screensaver:
    CommandLine|contains: 'shell32.dll,Control_RunDLL desk.cpl,screensaver,@screensaver'
filter_main_parent_cpl:  # Settings
    ParentImage: 'C:\Windows\System32\control.exe'
    ParentCommandLine|contains: '.cpl'
    CommandLine|contains|all:
        - 'Shell32.dll'
        - 'Control_RunDLL'
        - '.cpl'
filter_main_startmenu:
    ParentImage: 'C:\Windows\System32\control.exe'
    CommandLine|startswith: '"C:\Windows\system32\rundll32.exe" Shell32.dll,Control_RunDLL "C:\Windows\System32\'
    CommandLine|endswith: '.cpl",'
condition: selection and not 1 of filter_main_*

False positives (as the rule lists them)

• False positives depend on scripts and administrative tools used in the monitored environment

Tags

• attack.stealth
• attack.t1218.011

MITRE ATT&CK ids this rule names

• T1218.011

References

• http://www.hexacorn.com/blog/2017/05/01/running-programs-via-proxy-jumping-on-a-edr-bypass-trampoline/
• https://twitter.com/Hexacorn/status/885258886428725250
• https://gist.github.com/ryhanson/227229866af52e2d963cf941af135a52
• https://twitter.com/nas_bench/status/1433344116071583746
• https://twitter.com/eral4m/status/1479106975967240209
• https://twitter.com/eral4m/status/1479080793003671557

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/process_creation/proc_creation_win_rundll32_susp_activity.yml