curl URL sanitization vulnerability

                      curl URL sanitization vulnerability
                      ===================================

Project cURL Security Advisory, January 24th 2012
http://curl.haxx.se/docs/security.html

1. VULNERABILITY

   curl is vulnerable to a data injection attack for certain protocols through
   control characters embedded or percent-encoded in URLs.

   When parsing URLs, libcurl's parser is very laxed and liberal and only
   parses as little as possible and lets as much as possible through as long as
   it can figure out what to do.

   In the specific process when libcurl extracts the file path part from a
   given URL, it didn't always verify the data or escape control characters
   properly before it passed the file path on to the protocol-specific code
   that then would use it for its protocol business.

   This passing through of control characters could be exploited by someone who
   would be able to pass in a handicrafted URL to libcurl. Lots of libcurl
   using applications let users enter URLs in one form or another and not all
   of these check the input carefully to prevent malicious ones.

   A malicious user might pass in %0d%0a to get treated as CR LF by libcurl,
   and by using this fact a user can trick for example a POP3 client to delete
   a message instead of getting it or trick an SMTP server to send an
   unintended message.