A vulnerability in the Identity Services Engine (ISE) integration feature of Cisco Prime Infrastructure (PI) could allow an unauthenticated, remote attacker to perform a man-in-the-middle attack against the Secure Sockets Layer (SSL) tunnel established between ISE and PI. The vulnerability is due to improper validation of the server SSL certificate when establishing the SSL tunnel with ISE. An attacker could exploit this vulnerability by using a crafted SSL certificate and could then intercept communications between the ISE and PI. A successful exploit could allow the attacker to view and alter potentially sensitive information that the ISE maintains about clients that are connected to the network. This vulnerability affects Cisco Prime Infrastructure Software Releases 2.2 through 3.4.0 when the PI server is integrated with ISE, which is disabled by default.