Educause Security Discussion mailing list archives
Re: YAWiTR - Yet another what is the risk -- Virus Scanning Engine Flaw + RainbowCrack Online
From: "Hull, Dave" <dphull () KU EDU>
Date: Thu, 10 Nov 2005 14:05:56 -0600
Actually a full set of RC tables is about 64GB and includes all letters upper and lower, numbers and 32 symbols and a the space character. The way RC works is to split the LM hash into two 7 character strings. It scans the entire set of hashes for a match for the first seven characters and repeats the process for the second half of the password. In our testing, it takes about two or three minutes for a "good" password of eight characters including upper, lower and special characters. You can either disable the use of LM hashes or choose passwords longer than 14 characters which causes them to be NTLMv2 or some such. But no, simply adding a special character to the mix is not sufficient. -- Dave "DP" Hull, Network Security Analyst IT Security Office, A Division of Information Services The University of Kansas Desk: 785-864-0429 || Mobile: 785-840-7341 -----Original Message----- From: Chris Harrington [mailto:charrington () NITROSECURITY COM] Sent: Thursday, November 10, 2005 1:18 PM To: SECURITY () LISTSERV EDUCAUSE EDU Subject: Re: [SECURITY] YAWiTR - Yet another what is the risk -- Virus Scanning Engine Flaw + RainbowCrack Online Their NTLM hashes cover up to 8 character passwords, as long as the password does not have a symbol. Their LANMAN hashes are up to 7 character passwords. The easiest way to make sure you are not affected by this site is to: 1. Disable support for LANMAN if not needed. Here is a good link on how to: http://www1.umn.edu/oit/img/assets/5630/DisableLanMan.pdf 2. Include a symbol in your password policy. If you don't want to disable support for LANMAN you will need an 8 character password that has at least one symbol in it. Adding symbols to their Rainbow tables will add years to the time it will take to generate them. The same for 8 character LANMAN passwords. --Chris Christopher Harrington Chief Technology Officer nitrosecurity o: 603.766.8160 c: 603.969.0592 e: charrington () nitrosecurity com <mailto:charrington () nitrosecurity com> w: www.nitrosecurity.com <blocked::http://www.nitrosecurity.com/> ________________________________ From: James H Moore [mailto:jhmfa () RIT EDU] Sent: Thursday, November 10, 2005 1:58 PM To: SECURITY () LISTSERV EDUCAUSE EDU Subject: [SECURITY] YAWiTR - Yet another what is the risk -- Virus Scanning Engine Flaw + RainbowCrack Online - - - And between the time that I started writing this, and now, I also found out about RainbowCrack Online. How do you think that it will affect password standards, or increased use of 2-factor authentication?
Current thread:
- Re: YAWiTR - Yet another what is the risk -- Virus Scanning Engine Flaw + RainbowCrack Online Chris Harrington (Nov 10)
- <Possible follow-ups>
- Re: YAWiTR - Yet another what is the risk -- Virus Scanning Engine Flaw + RainbowCrack Online Jimmy Kuo (Nov 10)
- Re: YAWiTR - Yet another what is the risk -- Virus Scanning Engine Flaw + RainbowCrack Online John Duksta (Nov 10)
- Re: YAWiTR - Yet another what is the risk -- Virus Scanning Engine Flaw + RainbowCrack Online Hull, Dave (Nov 10)
- Re: YAWiTR - Yet another what is the risk -- Virus Scanning Engine Flaw + RainbowCrack Online Chris Harrington (Nov 10)
- Re: YAWiTR - Yet another what is the risk -- Virus Scanning Engine Flaw + RainbowCrack Online Hull, Dave (Nov 10)
- Re: YAWiTR - Yet another what is the risk -- Virus Scanning Engine Flaw + RainbowCrack Online Chris Harrington (Nov 10)
- Re: YAWiTR - Yet another what is the risk -- Virus Scanning Engine Flaw + RainbowCrack Online Chris Harrington (Nov 10)
- Re: YAWiTR - Yet another what is the risk -- Virus Scanning Engine Flaw + RainbowCrack Online Brian (Nov 10)
- Re: YAWiTR - Yet another what is the risk -- Virus Scanning Engine Flaw + RainbowCrack Online Russell Fulton (Nov 10)
- Re: YAWiTR - Yet another what is the risk -- Virus Scanning Engine Flaw + RainbowCrack Online Perry, Jeff (Nov 10)