clogin.php in Benchmark Designs' WHM AutoPilot 2.4.5 and earlier allows remote attackers to obtain plaintext username and password credentials by using the clogin_e and base64_encode functions to encode the desired user ID in the c parameter, then read the plaintext values in the resulting form.
https://exchange.xforce.ibmcloud.com/vulnerabilities/16849
http://www.securityfocus.com/bid/10846
http://secunia.com/advisories/12200
http://archives.neohapsis.com/archives/fulldisclosure/2004-07/1310.html