Information Assurance Day Course Cracking Passwords

Outline Introduction The Exercises Passwords & Hashes How do you get them? How can you abuse them? The Exercises Obtaining Hashes LiveCD Exploit Passive Sniffing Cracking Passwords

Introduction – Passwords & Hashes Passwords are used everywhere. The recommended best practice for storing them is to store them as a salted hash. Unix: $1$O3JMY.Tw$AdLnLjQ/5jXF9.MTp3gHv/ Windows LM: 855c3697d9979e78ac404c4ba2c66533 Windows NTLM: $NT$7f8fe03093cc84b267b109625f6bbf4b Salts are used to prevent cracking using precomputed hashes (rainbow tables) and bulk cracking. Talk a bit about passwords. Mention length, complexity, and keyspace - length is the best way to increase the keyspace. Explain salts. Windows LM Hashes are super easy to crack, which is why we love them: unsalted, case- insensitive, 14-char max length, split into two 7-char passwords. <3 Most modern Windows boxes still use the LM hashes for backwards compatibility!

Introduction – Obtaining Hashes In order to obtain password hashes, you must know where they are stored and how they are used. Hashes are usually stored locally on disk and are sometimes transmitted over the network. It follows then, that if we can somehow gain access to the disk or sniff some network traffic, we should be able to grab some password hashes.

Introduction – Abusing Hashes You now have some hashes. What can you do with them? Pass the Hash Attack (Windows) Crack them! John the Ripper Ophcrack rcracki