I'm glad to see this information was brought up when people state that some leak checks out due to hash numbers. What many don't realize is that the MD5 check sum numbers are still vulnerable where MS is taking that into consideration for 7.
"Vulnerability
Because MD5 makes only one pass over the data, if two prefixes with the same hash can be constructed, a common suffix can be added to both to make the collision more reasonable.
Because the current collision-finding techniques allow the preceding hash state to be specified arbitrarily, a collision can be found for any desired prefix; that is, for any given string of characters X, two colliding files can be determined which both begin with X.
All that is required to generate two colliding files is a template file, with a 128-byte block of data aligned on a 64-byte boundary, that can be changed freely by the collision-finding algorithm.
Recently, a number of projects have created MD5 "
rainbow tables" which are easily accessible online, and can be used to reverse many MD5 hashes into strings that collide with the original input, usually for the purposes of
password cracking. However, if passwords are combined with a
salt before the MD5 digest is generated, rainbow tables become much less useful.
The use of MD5 in some websites'
URLs means that
Google can also sometimes function as a limited tool for reverse lookup of MD5 hashes.
[11] This technique is rendered ineffective by the use of a
salt.
On December 30, 2008, a group of researchers announced at the 25th
Chaos Communication Congress how they had used MD5 collisions to create an intermediate certificate authority certificate which appeared to be legitimate when checked via its MD5 hash.
[5]. The researchers used a cluster of
Sony Playstation 3s at the
EPFL in Lausanne, Switzerland.
[12] to change a normal SSL certificate issued by RapidSSL into a working CA certificate for that issuer, which could then be used to create other certificates that would appear to be legitimate and issued by RapidSSL.
VeriSign, the issuers of RapidSSL certificates, said they stopped issuing new certificates using MD5 as their checksum algorithm for RapidSSL once the vulnerability was announced.
[13]"
MD5 - Wikipedia, the free encyclopedia
