Module 8 · AS-REP Roasting — The Quiet Cousin of Kerberoasting

Manish Garg
Manish Garg Associate of (ISC)² · RingSafe
Apr 27, 2026
2 min read
Read as

Last updated: April 29, 2026

100% Free

No signup. No paywall. No catch. One of our 10 most-requested practitioner modules — published in full so anyone can learn for free. We earn through consulting, not by gating knowledge.

See all 10 free modules →

Why this module exists. Every AD pentester checks Kerberoasting first. Most check AS-REP Roasting second. The astonishing thing is how often it works in 2026 — accounts with DONT_REQ_PREAUTH set, often “temporarily” by an admin in 2014 and never unset.

Why this module exists. Every AD pentester checks Kerberoasting first. Most check AS-REP Roasting second. The astonishing thing is how often it works in 2026 — accounts with DONT_REQ_PREAUTH set, often “temporarily” by an admin in 2014 and never unset. One vulnerable account is enough to crack a domain user’s password offline.

The bug, structurally

Kerberos pre-authentication: when you request a TGT, you must prove you know your password by encrypting a timestamp with a key derived from it. The KDC decrypts, checks the timestamp is recent, and if so issues the TGT.

If pre-auth is disabled (DONT_REQ_PREAUTH flag in userAccountControl), the KDC issues a TGT to anyone who asks, encrypted with the user’s password-derived key. An attacker requests, takes the encrypted TGT offline, and brute-forces the password.

Want this for your team?

Custom team training + practitioner advisory

Beyond the free academy — we run private workshops, vCISO advisory, and red-team exercises tailored to your stack. For Indian SMBs scaling past their first hire.

Book team training call Replies in 4 working hrs · India-only · Senior consultants