Re: IE 5.x keep-alive session hijacking

[3APA3A <3APA3A () SECURITY NNOV RU>]

Dear Domas Mituzas,

I can't confirm this behaviour for IE 5.5 and 6.0. May be behaviour your
observe is a result of customer having his own proxy server (for example
something  like proxymitron, or some kind of ad killer, etc) before your
transparent   proxy   and   customer's   proxy   server   doesn't  strip
Proxy-connection  header before resending reply to IE, so IE thinks this
header  comes  from  proxy.  This  should  be  treated  as  proxy server
vulnerability. 3proxy doesn't have one :)

--Tuesday, September 2, 2003, 1:17:41 PM, you wrote to bugtraq () securityfocus com:

DM> Hi,

DM> sorry for being innacurate, but I noticed that our transparent-proxy system is trying (and even to succeeds at some 
level) to hijack client http connections. I asked users to supply us with their
DM> browser versions, and all of resulted answers were MS Internet Explorer. I didn't have too much time to investigate 
this issue, but here's how I imagine the problem. The transparent reverse proxy
DM> provides with Proxy-Connection: header, that can be misinterpretated by MSIE, so the browser software directs all 
further requests via proxy solution. It is possible to answer positively to any
DM> request, so browser continues to use proxy server transparently. Though, we've got ACLs forbidding such usage of 
our proxy servers, one can use such MITM attack to get cookies, input data, etc.
DM> Possibly that can be caused sometimes on other browser configurations as well. 

DM> Best regards,
DM> Domas Mituzas
DM> MicroLink Data 


-- 
~/ZARAZA
Впрочем, важнее всего - алгоритм!  (Лем)