Secunia Security Advisory – A weakness has been reported in Sun Java System Access Manager, which can be exploited by malicious people to identify valid user accounts.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/74415/sa33688.txt
Source: https://packetstormsecurity.com/files/74415/Secunia-Security-Advisory-33688.html