Weakly-Encrypted Kerberos TGT Response

Cortex XSIAM Analytics Alert Reference by Alert name

Product
Cortex XSIAM
Last date published
2026-04-13
Category
Analytics Alert Reference
Index by
Alert name

Synopsis

Activation Period

14 Days

Training Period

30 Days

Test Period

N/A (single event)

Deduplication Period

1 Day

Required Data

  • Requires one of the following data sources:
    • Palo Alto Networks Firewall EAL Logs
      OR
    • XDR Agent

Detection Modules

Detector Tags

ATT&CK Tactic

ATT&CK Technique

Modify Authentication Process: Domain Controller Authentication (T1556.001)

Severity

Informational

Description

A weakly encrypted Kerberos TGT was issued by a domain controller. The encryption type is abnormal for this DC and results in a TGT that is easier to crack. This behavior may indicate a Skeleton Key attack.

Attacker's Goals

Manipulate the domain controller authentication process to bypass standard authentication and gain access to hosts and resources in environments relying on single-factor authentication.

Investigative actions

  • Identify the user or entity that requested the TGT during the alert timeframe.
  • Determine whether a legitimate service or application requested weak Kerberos encryption.
  • Verify whether the domain controller is patched against the Skeleton Key vulnerability (CVE-2016-1567).

Variations

Abnormal Weakly-Encrypted Kerberos TGT Response

Synopsis

ATT&CK Tactic

ATT&CK Technique

Modify Authentication Process: Domain Controller Authentication (T1556.001)

Severity

Low

Description

A weakly encrypted Kerberos TGT was issued by a domain controller. The encryption type is abnormal for this DC and results in a TGT that is easier to crack. This behavior may indicate a Skeleton Key attack.

Attacker's Goals

Manipulate the domain controller authentication process to bypass standard authentication and gain access to hosts and resources in environments relying on single-factor authentication.

Investigative actions

  • Identify the user or entity that requested the TGT during the alert timeframe.
  • Determine whether a legitimate service or application requested weak Kerberos encryption.
  • Verify whether the domain controller is patched against the Skeleton Key vulnerability (CVE-2016-1567).