Sigma rule: Suspicious Rejected SMB Guest Logon From IP

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-7f0b1d930092, updated 2023-01-02T00:00:00.000Z.

Rule

Title
Suspicious Rejected SMB Guest Logon From IP
Status
test
Level
medium
Author
Florian Roth (Nextron Systems), KevTheHermit, fuzzyf10w
Date
2021-06-30
Modified
2023-01-02
File
rules/windows/builtin/smbclient/security/win_smbclient_security_susp_failed_guest_logon.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detect Attempt PrintNightmare (CVE-2021-1675) Remote code execution in Windows Spooler Service

Log source

product
windows
service
smbclient-security

Detection

selection:
    EventID: 31017
    UserName: ''
    ServerName|startswith: '\1'
condition: selection

False positives (as the rule lists them)

  • Account fallback reasons (after failed login with specific account)

Tags

  • attack.credential-access
  • attack.t1110.001

MITRE ATT&CK ids this rule names

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/builtin/smbclient/security/win_smbclient_security_susp_failed_guest_logon.yml

Sources and licences

  • SigmaHQ

    "Suspicious Rejected SMB Guest Logon From IP" by Florian Roth (Nextron Systems), KevTheHermit, fuzzyf10w (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/builtin/smbclient/security/win_smbclient_security_susp_failed_guest_logon.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 Rejected SMB Guest Logon From IP",
entity page, dataset version ref-7f0b1d930092, updated 2023-01-02T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/71886b70-d7b4-4dbf-acce-87d2ca135262 (accessed 2026-11-03).
Underlying source: SigmaHQ rule 71886b70-d7b4-4dbf-acce-87d2ca135262, 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.