NmService.exe in Ipswitch WhatsUp Professional 2006 allows remote attackers to cause a denial of service (CPU consumption) via crafted requests to Login.asp, possibly involving the (1) "In]" and (2) "b;tnLogIn" parameters, or (3) malformed btnLogIn parameters, possibly involving missing "[" (open bracket) or "[" (closing bracket) characters, as demonstrated by "&btnLogIn=[Log&In]=&" or "&b;tnLogIn=[Log&In]=&" in the URL. NOTE: due to the lack of diagnosis by the original researcher, the precise nature of the vulnerability is unclear.
https://exchange.xforce.ibmcloud.com/vulnerabilities/24864
http://www.vupen.com/english/advisories/2006/0704
http://www.securityfocus.com/archive/1/425780/100/0/threaded