A vulnerability in the web interface of the Cisco Adaptive Security Appliance (ASA) 9.3(3) and 9.6(2) could allow an unauthenticated, remote attacker to determine valid usernames. The attacker could use this information to conduct additional reconnaissance attacks. The vulnerability is due to the interaction between Lightweight Directory Access Protocol (LDAP) and SSL Connection Profile when they are configured together. An attacker could exploit the vulnerability by performing a username enumeration attack to the IP address of the device. An exploit could allow the attacker to determine valid usernames. Cisco Bug IDs: CSCvd47888.