With the menace of hackers increasing every day, even well administrated networks are vulnerable to attack. Therefore, securing network assets has become a significant issue for the corporate world. Traditionally, the tools used for network security involve the firewall systems, the intrusion detection system (IDS), the anti-virus software, the vulnerability scanning software. Each of the above, used independently or in conjunction, is not capable of withstanding the onslaught of various network threats. To solve the problem, collaborative security paradigms, which integrate some security devices closely to provide accurate alerts and attain enhanced protection are emerging. In this paper we present a collaborative framework of vulnerability-based alert verification. Along with conducting systematic analyses on contextual information modeling, alert verification is applied above intrusion detection aimed at helping determine whether the attack was successful or not. Based on the confid...