Sigma rule: Suspicious Network Connection Binary No CommandLine

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-51ebfef7611c, updated 2022-07-03T00:00:00.000Z.

Rule

Title
Suspicious Network Connection Binary No CommandLine
Status
test
Level
high
Author
Florian Roth (Nextron Systems)
Date
2022-07-03
File
rules/windows/network_connection/net_connection_win_susp_binary_no_cmdline.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects suspicious network connections made by a well-known Windows binary run with no command line parameters

Log source

product
windows
category
network_connection

Detection

selection:
    Initiated: 'true'
    Image|endswith:
        - '\regsvr32.exe'
        - '\rundll32.exe'
        - '\dllhost.exe'
    CommandLine|endswith:
        - '\regsvr32.exe'
        - '\rundll32.exe'
        - '\dllhost.exe'
filter_no_cmdline:
    CommandLine: ''
filter_null: # e.g. Sysmon has no CommandLine field in network events with ID 3
    CommandLine: null
condition: selection and not 1 of filter*

False positives (as the rule lists them)

  • Unknown

Tags

  • attack.stealth

References

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/network_connection/net_connection_win_susp_binary_no_cmdline.yml

Sources and licences

  • SigmaHQ

    "Suspicious Network Connection Binary No CommandLine" by Florian Roth (Nextron Systems) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/network_connection/net_connection_win_susp_binary_no_cmdline.yml.
    Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License

    Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: Suspicious Network Connection Binary No CommandLine",
entity page, dataset version ref-51ebfef7611c, updated 2022-07-03T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/20384606-a124-4fec-acbb-8bd373728613 (accessed 2026-11-03).
Underlying source: SigmaHQ rule 20384606-a124-4fec-acbb-8bd373728613, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.