MD5 Considered Harmful Today: Creating a rogue CA certificate

2009.01.07
Risk: Medium
Local: No
Remote: Yes
CWE: CWE-310


CVSS Base Score: 5/10
Impact Subscore: 2.9/10
Exploitability Subscore: 10/10
Exploit range: Remote
Attack complexity: Low
Authentication: No required
Confidentiality impact: None
Integrity impact: Partial
Availability impact: None

Our research team, consisting of 7 researchers from the United States, Switzerland and the Netherlands, was able to execute a practical MD5 collision attack and create a rogue Certification Authority trusted by all common web browsers. This allows us to perform transparent man-in-the-middle attacks against SSL connections and monitor or tamper with the traffic to secure websites or email servers. The infrastructure of Certification Authorities is meant to prevent exactly this type of attack. Our work shows that known weaknesses in the MD5 hash function can be exploited in realistic attack, due to the fact that even after years of warnings about the lack of security of MD5, some root CAs are still using this broken hash function. More details: http://www.phreedom.org/research/rogue-ca/ Enjoy! Alex -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (Darwin) iEYEARECAAYFAklaUXEACgkQ6MVeVwnnQQStoQCdF5eIxqKx515soMee2sVgEACc N7AAn1gOtnDC5f1tqB/RxMpfZ1rY+wnU =Fpsd -----END PGP SIGNATURE-----

References:

https://blogs.verisign.com/ssl-blog/2008/12/on_md5_vulnerabilities_and_mit.php
http://www.win.tue.nl/hashclash/SoftIntCodeSign/
http://www.win.tue.nl/hashclash/rogue-ca/
http://www.securityfocus.com/bid/33065
http://www.securityfocus.com/archive/1/archive/1/499685/100/0/threaded
http://www.phreedom.org/research/rogue-ca/
http://www.microsoft.com/technet/security/advisory/961509.mspx
http://www.doxpara.com/research/md5/md5_someday.pdf
http://blogs.technet.com/swi/archive/2008/12/30/information-regarding-md5-collisions-problem.aspx
http://blog.mozilla.com/security/2008/12/30/md5-weaknesses-could-lead-to-certificate-forgery/


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