Sigma rule: Cleartext Protocol Usage

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-cf694c9d469c, updated 2022-10-10T00:00:00.000Z.

Rule

Title
Cleartext Protocol Usage
Status
stable
Level
low
Author
Alexandr Yampolskyi, SOC Prime, Tim Shelton
Date
2019-03-26
Modified
2022-10-10
File
rules/network/firewall/net_firewall_cleartext_protocols.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Ensure that all account usernames and authentication credentials are transmitted across networks using encrypted channels.
Ensure that an encryption is used for all sensitive information in transit. Ensure that an encrypted channels is used for all administrative account access.

Log source

category
firewall

Detection

selection:
    dst_port:
        - 8080
        - 21
        - 80
        - 23
        - 50000
        - 1521
        - 27017
        - 3306
        - 1433
        - 11211
        - 15672
        - 5900
        - 5901
        - 5902
        - 5903
        - 5904
selection_allow1:
    action:
        - forward
        - accept
        - 2
selection_allow2:
    blocked: "false" # not all fws set action value, but are set to mark as blocked or allowed or not
condition: selection and 1 of selection_allow*

False positives (as the rule lists them)

  • Unknown

Tags

  • attack.credential-access

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/network/firewall/net_firewall_cleartext_protocols.yml

Sources and licences

  • SigmaHQ

    "Cleartext Protocol Usage" by Alexandr Yampolskyi, SOC Prime, Tim Shelton (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/network/firewall/net_firewall_cleartext_protocols.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: Cleartext Protocol Usage",
entity page, dataset version ref-cf694c9d469c, updated 2022-10-10T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/d7fb8f0e-bd5f-45c2-b467-19571c490d7e (accessed 2026-11-03).
Underlying source: SigmaHQ rule d7fb8f0e-bd5f-45c2-b467-19571c490d7e, 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.