Sigma rule: Weak Encryption Enabled and Kerberoast

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-7cd9e96448a7, updated 2021-11-27T00:00:00.000Z.

Rule

Title: Weak Encryption Enabled and Kerberoast
Status: test
Level: high
Author: @neu5ron
Date: 2017-07-30
Modified: 2021-11-27
File: rules/windows/builtin/security/win_security_alert_enable_weak_encryption.yml
Commit: ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects scenario where weak encryption is enabled for a user profile which could be used for hash/password cracking.

Log source

product: windows
service: security
definition: Requirements: Audit Policy : Account Management > Audit User Account Management, Group Policy : Computer Configuration\Windows Settings\Security Settings\Advanced Audit Policy Configuration\Audit Policies\Account Management\Audit User Account Management

Detection

selection:
    EventID: 4738
# According to Microsoft, the bit values are listed here: https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-10/security/threat-protection/auditing/event-4720
# However, that seems to be a simple copy from https://learn.microsoft.com/en-us/troubleshoot/windows-server/active-directory/useraccountcontrol-manipulate-account-properties
# and the actual flags that are used are quite different and, unfortunately, not documented.
# https://github.com/mdecrevoisier/EVTX-to-MITRE-Attack/ contains a number of EVTX files with relevant events, which can be used to extract
# the following values.
olduac_des: # 0x8000
    OldUacValue|endswith:
        - 8???
        - 9???
        - A???
        - B???
        - C???
        - D???
        - E???
        - F???
newuac_des:
    NewUacValue|endswith:
        - 8???
        - 9???
        - A???
        - B???
        - C???
        - D???
        - E???
        - F???
olduac_preauth: # 0x10000
    OldUacValue|endswith:
        - 1????
        - 3????
        - 5????
        - 7????
        - 9????
        - B????
        - D????
        - F????
newuac_preauth:
    NewUacValue|endswith:
        - 1????
        - 3????
        - 5????
        - 7????
        - 9????
        - B????
        - D????
        - F????
olduac_encrypted: # 0x800
    OldUacValue|endswith:
        - 8??
        - 9??
        - A??
        - B??
        - C??
        - D??
        - E??
        - F??
newuac_encrypted:
    NewUacValue|endswith:
        - 8??
        - 9??
        - A??
        - B??
        - C??
        - D??
        - E??
        - F??
condition: selection and ((newuac_des and not olduac_des) or (newuac_preauth and not olduac_preauth) or (newuac_encrypted and not olduac_encrypted))

False positives (as the rule lists them)

Unknown

MITRE ATT&CK ids this rule names

T1685

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/security/win_security_alert_enable_weak_encryption.yml

Sources and licences

SigmaHQ
"Weak Encryption Enabled and Kerberoast" by @neu5ron (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/builtin/security/win_security_alert_enable_weak_encryption.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: Weak Encryption Enabled and Kerberoast",
entity page, dataset version ref-7cd9e96448a7, updated 2021-11-27T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/f6de9536-0441-4b3f-a646-f4e00f300ffd (accessed 2026-11-03).
Underlying source: SigmaHQ rule f6de9536-0441-4b3f-a646-f4e00f300ffd, 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.