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38. Active Directory Attacks and Defence

38.5 NTLM Relay and Pass-the-Hash Concepts (Lab Only)

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Pass-the-Hash (PtH): NTLM hash milala (example: from memory dump on a machine YOU own) tar password crack shivay authenticate – protocol design. NTLM relay: coerce/auth capture → forward to another service that accepts NTLM without signing/channel binding.

Impacket names Blue must know to stop: ntlmrelayx.py, secretsdump.py (DCSync / SAM dump styles need high privilege – only on YOUR lab DC after you grant rights). Frame: "What must Blue disable so these fail?"

Blue controls: SMB signing required; LDAP signing + channel binding; disable NTLM where feasible; LAPS / Windows LAPS for unique local admin passwords; Credential Guard; Protected Users group for admins; Tier model (DA never logs into Tier-2 workstation); EPA for AD CS if used.

Red team (attacker) does Blue team (defender) detects / stops
Relays NTLM to LDAP/SMB/HTTP when signing off Enforce SMB signing; LDAP signing + channel binding; Extended Protection
Pass-the-Hash with stolen NTLM Credential Guard; LSA protection; disable NTLM; rotate on compromise
secretsdump.py style dump after DA Alert DCSync-like replication rights abuse (4662); Tier-0 hardening; PAM / JIT admin

Ravindra Bagale's Tip

Students see secretsdump succeed and upload a video. That is lab proof – publicly dumping even lab hashes is careless. Focus on the interview answer: "SMB signing and LDAP channel binding stop many relays; LAPS stops lateral with one local hash." Defence sentence first, tool name later.

Practice task

Notes madhe 6-row table: control (SMB signing / LDAP signing / channel binding / LAPS / Credential Guard / Tier model) | kay rokto | lab madhe kasa verify (high level). Amir (fictional junior SOC) la 8-line mail draft: "Why DA interactive logon on a Win10 helpdesk PC is dangerous."

Real incident: identity + lateral lessons after major worm outbreaks (2017)

Public post-incident writing on NotPetya/EternalBlue-era movement stressed that once credential material and SMB trust were available, many networks saw rapid east-west spread. Reported lesson for defenders: patch, segment, reduce NTLM, unique local passwords (LAPS). Source: national CERT and major vendor postmortems (verify).

Extended teaching notes

Why this lesson matters

Cryptography fails when people invent it. Use standard libraries, modern algorithms (AES-GCM, TLS 1.2+, bcrypt/argon2) and protect keys in a KMS or secrets manager.

Where crypto shows up

[('Passwords', 'bcrypt/argon2/PBKDF2 via the framework hasher — never plain MD5/SHA1.'), ('TLS', "Terminate on ALB/nginx with ACM/Let's Encrypt; redirect HTTP to HTTPS."), ('JWT / API tokens', 'Short lifetime, rotate signing keys, store secrets outside Git.'), ('Disk / S3', 'Provider or customer-managed keys; least privilege on decrypt.')]

Mini case study

Suppose we are on a purple-team exercise for an Indian mid-size company (sample data). Red notes a technique from this lesson against a lab clone. Blue must show the control that stops it, the log that would have fired, and the ticket that hardens production. That is the standard this course trains you for.

Defender's worksheet (do this today)

  1. Write the lesson title, date and the exact lab target you are allowed to use.
  2. List three owned systems (VMs, apps, or cloud accounts) where this lesson applies.
  3. Run one safe check from the lesson on a lab system only. Paste the command and output.
  4. Write a two-sentence fix you would give a teammate.
  5. Name one related public advisory (CERT-In, CISA, NVD, or a vendor bulletin) with its date.

Indian workplace (sample data)

Suppose we are a junior analyst at Infosys, TCS, Wipro or a fintech SOC in Bengaluru/Pune. Turn this lesson into one checklist item with an owner, a due date and a place to store evidence (ticket + screenshot).

Global practice

Compare your notes with OWASP, CIS Benchmarks, NIST CSF/IR guidance or a cloud Well-Architected security question. Write five lines on what overlaps.

Everyday analogy

Explain the risk and the fix to a family member without jargon. If they can repeat the warning, you understand it well enough to teach juniors.

Key terms

  • Control: a safeguard (patch, config, process, detection).
  • Finding: a weakness backed by evidence.
  • Remediation: the fix plus how you verified it.
  • Scope: systems you have written permission to touch.
  • Least privilege: only the access the task needs.
  • Defence in depth: several layers so one failure does not end the story.

Common mistakes

  • Skipping written permission "just for a quick scan".
  • Practising on hostel, office or public targets without authorisation.
  • Collecting tool output without writing the fix.
  • Copying attack steps onto production to "verify". Defenders verify with versions, configs and patches.
  • Publishing screenshots that contain secrets, cookies or internal hostnames.

Recap

  • Evidence, fix, owner, date.
  • Own lab only.
  • Fix > spectacle.