Sigma rule: Rundll32 UNC Path Execution

Rule

Title

Rundll32 UNC Path Execution

Status

test

Level

high

Author

Nasreddine Bencherchali (Nextron Systems)

Date

2022-08-10

Modified

2026-07-20

File

rules/windows/process_creation/proc_creation_win_rundll32_unc_path.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects rundll32 execution where the DLL is located on a remote location (share).
Threat actors can abuse the rundll32.exe binary to execute remote DLLs from a UNC pathh.

Log source

product

windows

category

process_creation

Detection

selection_img:
    - Image|endswith: '\rundll32.exe'
    - OriginalFileName: 'RUNDLL32.EXE'
    - CommandLine|contains: 'rundll32'
selection_cli:
    CommandLine|contains:
        - ' \\\\'
        - ' ''\\\\'
        - ' "\\\\'
filter_main_cli_pipe:
    CommandLine|contains: '\\\\.\\pipe'
condition: all of selection_* and not 1 of filter_main_*

False positives (as the rule lists them)

• Unlikely

Tags

• attack.execution
• attack.lateral-movement
• attack.stealth
• attack.t1021.002
• attack.t1218.011

MITRE ATT&CK ids this rule names

• T1021.002
• T1218.011

References

• https://www.cybereason.com/blog/rundll32-the-infamous-proxy-for-executing-malicious-code
• https://www.microsoft.com/en-us/security/blog/2026/07/16/acr-stealer-two-observed-intrusion-chains-amid-increased-threat-activity/

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_unc_path.yml