Advisories : Microsoft Internet Explorer proxy server bypass

[EN] securityvulns.ru
no-pyccku




  Problem:  IE5  doesn't  use  proxy for FTP connection if option
  "Enable  folder  view  for  FTP  sites"  is  checked. This option is
  checked by default.
  Configuration: tested in 2 configurations:
   1. Windows NT 4.0 wrkst + SP5 + IE5.0
   2. Windows NT 4.0 wrkst + SP6a + IE5.01
  both has a problems.
  There is no problem under SP5 + IE401SP1a

  Description:

   FTP  proxy  address may be  set in browser configuration (or option 
   "use one proxy for all protocols" is checked), but IE5 doesn't uses
   the proxy for data connection, but  tries  to use direct connection
   instead.  Since IE5 uses active ftp mode and couldn't be configures
   to  use  passive  (that  isn't  good)  this  fact makes problem for
   firewalling.