Kerberoasting
A burst of Kerberos service-ticket requests (Event ID 4769) using RC4-HMAC encryption (Ticket Encryption Type 0x17).
What it detects
A burst of Kerberos service-ticket requests (Event ID 4769) using RC4-HMAC encryption (Ticket Encryption Type 0x17). Attackers request service tickets for many service accounts and crack them offline for the account passwords — "Kerberoasting". RC4 tickets are the crackable ones, so a run of RC4 TGS requests from one account, especially against many services, is the signal.
MITRE ATT&CK mapping
- T1558.003Steal or Forge Kerberos Tickets: Kerberoasting· Credential Access
False positives and triage
Some legacy applications still request RC4 tickets legitimately. The signal is a BURST of RC4 (0x17) service-ticket requests from one account, or requests spanning many distinct service accounts in a short time. Correlate with the requesting account and whether AES is otherwise standard in the domain.
The rule
Declarative YAML read by the detection engine — data, never executed. Confidence 70%. Source: rules/windows/kerberoasting.yaml, licensed under the Apache License 2.0.
id: windows.credential.kerberoasting
version: 1.0.0
status: stable
severity: high
confidence: 0.7
platforms: [windows]
mitre_techniques: [T1558.003]
description: |
A burst of Kerberos service-ticket requests (Event ID 4769) using RC4-HMAC
encryption (Ticket Encryption Type 0x17). Attackers request service tickets for
many service accounts and crack them offline for the account passwords —
"Kerberoasting". RC4 tickets are the crackable ones, so a run of RC4 TGS
requests from one account, especially against many services, is the signal.
match:
native_event_id: 4769
raw_message_contains_any:
- "0x17"
threshold:
count: 10
window_seconds: 600
group_by: [user_name]
correlation_keys: [user_name]
false_positive_guidance: |
Some legacy applications still request RC4 tickets legitimately. The signal is a
BURST of RC4 (0x17) service-ticket requests from one account, or requests
spanning many distinct service accounts in a short time. Correlate with the
requesting account and whether AES is otherwise standard in the domain.
Related detections
Run this rule on your own logs — offline
KIROSEC runs this rule and the rest of the library over Windows, Linux, macOS and cloud audit logs on the analyst's own machine. Every alert links to the events that raised it, and nothing leaves the device.