GPEN Kerberos Attacks Practice Question
During a penetration test, a tester compromises a workstation and extracts a Kerberos TGT for a domain user from memory. The tester wants to use this TGT to access a file share on a remote server without knowing the user's password. Which action should the tester take?
⚠ Common exam trap
The trap here is assuming a TGT can be cracked or used to derive the user's hash, when it must instead be injected into a session to request service tickets.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Inject the TGT into the current session using Rubeus ptt and request a service ticket for the file share's SPN.
Injecting a stolen TGT into the current session allows the system to request service tickets as the compromised user, enabling access to resources like file shares without the password. Pass-the-ticket leverages the TGT's validity until expiration, making it a powerful lateral movement technique.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Perform an S4U2Self request to obtain a service ticket for the file share using the extracted TGT.
Why it's wrong here
S4U2Self is used for protocol transition in delegation scenarios and requires the service to have a TGT for itself, not for an arbitrary user. It does not directly grant access to a file share on behalf of the user whose TGT was stolen. This technique is unrelated to simple pass-the-ticket access.
- ✗
Forge a new TGT using the user's NTLM hash, which can be derived from the extracted TGT.
Why it's wrong here
The user's NTLM hash cannot be derived from a TGT, as the TGT is encrypted with the krbtgt key and does not contain the user's password hash. Forging a TGT requires the krbtgt hash, which is not available. This method is based on a misunderstanding of Kerberos ticket structure.
- ✗
Crack the TGT offline to recover the user's password, then authenticate normally to the file share.
Why it's wrong here
A TGT is encrypted with the krbtgt account's key, not the user's password, so it cannot be cracked to reveal the user's password. Offline cracking of a TGT is not feasible without the krbtgt key. This approach fails and does not leverage the stolen ticket for access.
- ✓
Inject the TGT into the current session using Rubeus ptt and request a service ticket for the file share's SPN.
Why this is correct
Pass-the-ticket involves injecting a stolen TGT into a logon session so the system can request service tickets on behalf of the user. With the TGT injected, the tester can obtain a TGS for the file share's SPN and access it without the password. Rubeus ptt performs the injection, and the resulting TGS enables authenticated access.
About these practice questions
Courseiva writes every GPEN question from scratch — 298 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official GIAC exam blueprint
This GPEN practice question is part of Courseiva's free GIAC certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the GPEN exam.