Both Microsoft and Cisco released fixes for the vulnerabilities on Tuesday. The flaws were identified several years ago and were made public last year by two researchers at Outpost24, Jack C. Louis and Robert E. Lee. They notified vendors about the problems in 2008, but the process of fixing the vulnerability was a long one, given the huge number of vendors and products affected. To exploit these vulnerabilities, an attacker must be able to complete a. TCP three-way handshake with a vulnerable system.
Source: https://threatpost.com/microsoft-cisco-issue-patches-tcp-dos-flaw-090809/72286/