kb2661254

KB2661254 is a security update for Microsoft Windows that restricts the use of RSA certificates with key lengths less than 1024 bits. This update addresses a vulnerability where short RSA keys could be derived by an attacker, potentially allowing fraudulent certificate use for spoofing content or phishing. The update was revised in October 2012 (version 2.0) to rerelease for Windows XP and to offer it via automatic updating for all supported Windows releases. Customers who already applied the update do not need to take further action. This update is part of Microsoft's ongoing efforts to strengthen certificate security and protect against key-based attacks.