NTLM is the Floppy Disk of Authentication (And How Kerberos Saves Your Network)

You are currently viewing NTLM is the Floppy Disk of Authentication (And How Kerberos Saves Your Network)

NTLM is the Floppy Disk of Authentication (And How Kerberos Saves Your Network)

NTLM is the Windows XP of Security Protocols

Picture this: It’s 2024, and your company’s security team is still using NTLM (Windows NT Lan Manager) for authentication. You might as well host sensitive data on a Geocities page. NTLM is older than TikTok dances, more brittle than a stale cookie, and about as secure as a screen door on a submarine.

I once worked with a client who swore NTLM was “good enough.” Three breach attempts later, they paid me double to migrate to Kerberos. Let’s break down why clinging to NTLM is like trusting a padlock from the Dollar Store to guard Fort Knox.

1. NTLM 101: A Protocol Stuck in the ‘90s

NTLM debuted in 1993 (same year Jurassic Park hit theaters) and acts like a grumpy bouncer checking passwords. It’s still lurking in corporate networks, even though Microsoft has been begging users to ditch it since 2000.

How it (barely) works:

  1. User sends username + password to server.
  2. Server creates a hash (a jumbled version of your password).
  3. Server checks hash against its database → Grants access if it matches.

The problem? This is the cybersecurity equivalent of writing your PIN on a Post-It note.

2. Why NTLM is a Hacker’s Best Friend

A. The Password Hash is Low-Hanging Fruit

NTLM stores passwords as LM or NTLM hashes, which are easier to crack than a walnut at a squirrel convention. Tools like Mimikatz extract these hashes in seconds:

“`powershell

Mimikatz command to dump NTLM hashes

mimikatz.exe “privilege::debug” “sekurlsa::logonpasswords”

Real-world impact: In 2021, 80% of ransomware attacks leveraged stolen NTLM hashes (source) .

B. Pass-the-Hash Attacks: “I’ll Take That, Thanks”

Hackers don’t even need your password—just the hash. Pass-the-Hash (PtH) attacks let them impersonate you without breaking a sweat.

Ever seen a horror movie where the killer steals someone’s face? Yeah, it’s like that.

C. No Encryption? Seriously?

NTLM doesn’t encrypt authentication traffic by default. Hackers sniffing your network can intercept credentials faster than you can say “unsecured Wi-Fi.”

Pro Tip: If you must use NTLM, enforce SMB Signing and NTLMv2. But really, just stop.

3. Replay Attacks: NTLM’s Greatest Hits Album

How it works:

  1. Hacker records your authentication traffic.
  2. Replays it later to impersonate you.

Think of it as a broken record player that only plays “I’m a hacker now” on loop.

Why Kerberos fixes this: It uses timestamps and session-specific tickets. Replay old Kerberos tickets? They’ll expire faster than milk.

4. No Mutual Authentication? Trust Issues Incoming

NTLM only verifies the client’s identity. The server’s identity? Eh, whatever. This opens the door to man-in-the-middle (MitM) attacks.

Kerberos, meanwhile, validates both sides. It’s like a DNA test for servers.

5. Kerberos: The Jedi Knight of Authentication

Kerberos (named after the three-headed dog from Greek mythology) is NTLM’s glow-up. Microsoft adopted it in Windows 2000, and it’s still the gold standard.

How it works:

  1. Authentication Server (AS): You log in → AS gives you a Ticket-Granting Ticket (TGT).
  2. Ticket-Granting Server (TGS): Request access to a service (e.g., SharePoint) → TGS issues a service ticket.
  3. Service Server: Validate ticket → Access granted.

Why it’s better:

  • Encrypts everything: Like a VPN for your credentials.
  • Short-lived tickets: Even if stolen, they expire quickly.
  • Delegation support: Lets apps act on your behalf securely.

Fun Fact: Setting up Kerberos feels like assembling a Death Star Lego set. Frustrating at first, but glorious when it works.

6. How to Ditch NTLM (Without Breaking Everything)

Step 1: Find NTLM Dependencies

Run this PowerShell command to audit NTLM usage:

powershell
Get-WinEvent -LogName Security -FilterXPath “[System[EventID=4624]]” | Where-Object { $_.Message -like “NTLM*” }
“`

Step 2: Enforce Kerberos Where Possible

Update Group Policy:

  • Navigate to Computer Configuration > Windows Settings > Security Settings > Local Policies > Security Options.
  • Set Network security: Restrict NTLM to Deny all.

Step 3: Test, Test, Test

Mission-critical app breaks? Use Compatibilty Support Modules (CSMs) temporarily. But treat CSMs like duct tape—it’s not a long-term fix.

NTLM vs. Kerberos: A Side-by-Side Roast

FeatureNTLMKerberos
EncryptionOptional (LOL)Mandatory
Mutual Auth❌ Nope✅ Yes
DelegationClunky and unsafeSmooth and secure
SpeedSlow (multiple handshakes)Fast (single ticket)
Hacker Approval🌟🌟🌟🌟🌟🌟 (Too hard to crack)

But Wait—When is NTLM Actually Okay?

Legacy systems running software older than Avril Lavigne’s first album. If migrating breaks your ERP from 1998, use NTLM temporarily (with firewalls tighter than a hipster’s jeans).

Final Thought: Your Mom Was Right—Update Your Stuff

NTLM is a relic. Kerberos is the future. Migrating might feel like teaching your grandpa to use TikTok, but the security gains are worth it.

“The prudent sees danger and hides himself, but the simple go on and suffer for it.”
— Proverbs 22:3 (ESV)

…consider this your warning, folks.

Tag along for more tech exorcisms (of legacy systems):

|| Support the cause ||

Stay secure, stay sarcastic. 💻🛡️

Tags: , , , , , ,