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Microsoft Security Advisory 961509

MD5 hashes have been shown to be weak for a while now, and this is just yet another attack using these known weaknesses. These certificates are always signed using SHA-1 and as such are not affected by this newly reported research.General Information Overview Purpose of Advisory: To assist customers in assessing the impact of We would like to thank the engineers who helped build the above guidance: Eric Lawrence from the Internet Explorer team Kelvin Yiu and Tom Albertson from the Windows Cryptography team Maarten The company added that it wasn't aware of any actual attacks using the techniques described by an international team of researchers from Germany, the Netherlands, Switzerland and the U.S. navigate here

Thus, in the event that a malicious certificate is being actively used then a Certificate Authority can revoke it and Internet Explorer will automatically block the web-site visited. This new disclosure does not increase risk to customers significantly, as the researchers have not published the cryptographic background to the attack, and the attack is not repeatable without this information. Yes, my password is: Forgot your password? Mitigating Factors: General Information Top of sectionTop of sectionTop of section Resources: Disclaimer: The information provided in this advisory is provided "as is" without warranty of any kind.

Technologies that use a signing mechanism other than MD5 have been available for some time, and the use of MD5 as a hashing algorithm for signing purposes has been discouraged and The root cause of the problem is a known weakness of the MD5 algorithm which exposes it to collision attacks. Sadly, some very popular CAs do use MD5s.

SHA1 is universally supported by current SSL libraries. We appreciate your feedback. Advisory Status: Issue Confirmed. In the Security area, select the Check for publisher’s certificate revocation and Check for server certificate revocation check box.

Serious weaknesses in MD5 have been known for many years now; it is because of these weaknesses that MD5 is banned in new code under the Microsoft Security Development Lifecycle (SDL). more here: http://www.pcworld.com/businesscenter/arti...osoft_says.html >>>>>>>>>>>>>>>>>>>>>>> Share this post Link to post Share on other sites Create an account or sign in to comment You need to be a member in order to Steps to Configure Custom OCSP Responder Location Locally on Vista SP1 and Windows Server 2008: Start the Certificates MMC snap-in Click on the Start button and enter mmc.exe into the Start Your browser includes a set of trusted certificate authorities.

The MD5 algorithm had previously shown a vulnerability, but a practical attack had not yet been demonstrated. An attacker will have to lure a user to initiate an SSL/TLS connection, then the certificate will be validated by the client and it will seem valid. This attack is not a "game changer". It depends on who you got your certificate from.

Why switch to SHA1 and not RIPEMD/SHA2... This new disclosure does not increase risk to customers significantly, as the researchers have not published the cryptographic background to the attack, and the attack is not repeatable without this information. The more you can limit it, the better. See below link for more information: http://www.microsoft.com/technet/prodtechnol/ie/reskit/6/part2/c06ie6rk.mspx?mfr=true Reviewing the certificate Another alternative to verify whether the certificate is using MD5 is to look at the certificate details.

So a resonable size botnet would do it probably faster. check over here Post to Cancel %d bloggers like this: Threat Level: green Handler on Duty: Brad Duncan SANS ISC: MD5 SSL Summary - SANS Internet Storm Center SANS Site Network Current Site Internet Sign Up This Topic All Content This Topic This Forum Advanced Search Blog Browse Forums Calendar Staff Online Users More Activity All Activity My Activity Streams Unread Content Content I Started Several alternative and more secure technologies are available, including SHA-1, SHA-256, SHA-384 or SHA-512.

Bad. Fill in your details below or click an icon to log in: Email (required) (Address never made public) Name (required) Website You are commenting using your WordPress.com account. (LogOut/Change) You are But we will survive. his comment is here Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

I just joined the Microsoft Security Response Center a few months ago, and am the program manager working on the issue described in Microsoft Security Advisory (961509), which we just released. The MD5 algorithm had previously shown a vulnerability, but a practical attack had not yet been demonstrated. WIndows Sharing Problem, Please help Translate © 2017 Advanced PC Media LLC, all rights reserved.

News Extraordinary Robot News FeedJoined:Jun 27, 2006Messages:26,340Likes Received:20 Revision Note: Advisory published Summary: Microsoft is aware that research was published at a security conference proving a successful attack against X.509 digital

Microsoft Customer Support Microsoft Community Forums United States (English) Sign in Security TechCenter Home Security Updates Tools Learn Library Support We’re sorry. Not much. Windows Forum Windows Help and Support Forums > Windows Security > Security Alerts > Windows Tweaks Windows 8 Windows 7 Windows Vista Windows XP Servers Software Books WinGeek Forum Microsoft Security What protocols other then HTTPS are affected Everything that uses SSL.

The researchers uses a cluster of 200 Playstation3 systems, and it took them a couple days. What do I have to do? The protocol impacted the most is probably HTTPS. weblink Customers should contact their issuing Certificate Authority for guidance.• When visited, Web sites that use Extended Validation (EV) certificates show a green address bar in most modern browsers.

Mitigations & Workarounds Green filled address bar (IE7 & IE8) Extended Validation certificates (http://www.cabforum.org/EV_Certificate_Guidelines.pdf) are required to use SHA1 (instead of MD5) Thus, these certificates are not affected by this problem. See http://blogs.msdn.com/ie/archive/2006/11/07/improving-ssl-extended-validation-ev-ssl-certificates-coming-in-january.aspx for more information. Sign In Sign In Remember me Not recommended on shared computers Sign in anonymously Sign In Forgot your password? In a security advisory, Microsoft acknowledged the disclosure earlier in the day of an exploit of long-known bugs in the MD5 hashing algorithm used to create the digital certificates that in

General Information Overview Purpose of Advisory: To assist customers in assessing the impact of this research announcement on their current certificate deployments. Lastly, we should note that certificates hashed with SHA1 are not affected by this problem. Note: You must remove the root CA certificate from the Third Party Certification Authorities store from each computer manually prior to applying this policy Right click on the Trusted Root Certification No Security Update Planned.Recommendation: Review the suggested actions and configure as appropriate.References Identification Microsoft Knowledge Base Article 961509http://www.microsoft.com/technet/security/...ory/961509.mspx Share this post Link to post Share on other sites Peaches UberTechie

Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply. Affected Software None. These certificate authorities have to change the way they do business (e.g. The protocol is not "broken".

No. Register a new account Sign in Already have an account? Caveat: If the rogue certificate has misleading information about the CRL then web browsers might not be able to identify the certificate as revoked.