Sigma rule: PUA - Ngrok Execution

Rule

Title

PUA - Ngrok Execution

Status

test

Level

high

Author

Florian Roth (Nextron Systems)

Date

2021-05-14

Modified

2023-02-21

File

rules/windows/process_creation/proc_creation_win_pua_ngrok.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects the use of Ngrok, a utility used for port forwarding and tunneling, often used by threat actors to make local protected services publicly available.
Involved domains are bin.equinox.io for download and *.ngrok.io for connections.

Log source

product

windows

category

process_creation

Detection

selection1:
    CommandLine|contains:
        - ' tcp 139'
        - ' tcp 445'
        - ' tcp 3389'
        - ' tcp 5985'
        - ' tcp 5986'
selection2:
    CommandLine|contains|all:
        - ' start '
        - '--all'
        - '--config'
        - '.yml'
selection3:
    Image|endswith: 'ngrok.exe'
    CommandLine|contains:
        - ' tcp '
        - ' http '
        - ' authtoken '
selection4:
    CommandLine|contains:
        - '.exe authtoken '
        - '.exe start --all'
condition: 1 of selection*

False positives (as the rule lists them)

• Another tool that uses the command line switches of Ngrok
• Ngrok http 3978 (https://learn.microsoft.com/en-us/azure/bot-service/bot-service-debug-channel-ngrok?view=azure-bot-service-4.0)

Tags

• attack.command-and-control
• attack.t1572

MITRE ATT&CK ids this rule names

• T1572

References

• https://ngrok.com/docs
• https://www.fireeye.com/blog/threat-research/2021/05/shining-a-light-on-darkside-ransomware-operations.html
• https://stackoverflow.com/questions/42442320/ssh-tunnel-to-ngrok-and-initiate-rdp
• https://www.virustotal.com/gui/file/58d21840d915aaf4040ceb89522396124c82f325282f805d1085527e1e2ccfa1/detection
• https://cybleinc.com/2021/02/15/ngrok-platform-abused-by-hackers-to-deliver-a-new-wave-of-phishing-attacks/
• https://twitter.com/xorJosh/status/1598646907802451969
• https://www.softwaretestinghelp.com/how-to-use-ngrok/

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_pua_ngrok.yml