Strange IE / Windows Behaviour

[Paul Brereton <paul.brereton () it-security-audit com>]

 Guys,

 I noticed that when you request a long url using IE in wither windows 
 2000 or windows XP for example: 
 http://www.somehost.com/exisingfile.htm?
 aaaaaaaaaaaaaaaaaaaaa[about 256 times or so], the webpage takes on a
 different name when saving to disk such as QUFOU28S.htm . This also
 happens when you attemp to download a file with a long url ie: .gif?
 aaaaaaaaaaaaaaaaaaaaaaa etc,....

 Also, the more aaaaaa's that are appended, the different the response 
 is.

 My questions are :

 1.) Is this a small hashing functionality built into windows to 
 prevent long filenames from being downloaded and causing problems.

 or

 2.) Is it a screw up in windows? Possibly a buffer overflow?. I have 
 noticed that this type of naming is used for some temprorary files. 
 What is going on.

 RFCP (Request for comments please) :-)

 Regards,

 Paul.