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[SECURITY ADVISORY] cookie leak with IP address as domain

From: Daniel Stenberg <>
Date: Wed, 10 Sep 2014 08:40:15 +0200 (CEST)

                 libcurl cookie leak with IP address as domain

Project cURL Security Advisory, September 10th 2014


   By not detecting and rejecting domain names for partial literal IP addresses
   properly when parsing received HTTP cookies, libcurl can be fooled to both
   sending cookies to wrong sites and into allowing arbitrary sites to set
   cookies for others.

   For this problem to trigger, the client application must use the numerical
   IP address in the URL to access the site and the site must send back cookies
   to the site using domain= and a partial IP address.

   Since libcurl wrongly approaches the IP address like it was a normal domain
   name, a site at IP address can set cookies for anything ending
   with .168.0.1 thus fooling libcurl to send them also to for example

   The flaw requires dots to be present in the IP address, which restricts the
   flaw to IPv4 literal addresses or IPv6 addresses using the somewhat unusual
   "dotted-quad" style: "::ffff:"

   This is not believed to be done by typical sites as this is not supported by
   clients that adhere to the rules of the RFC 6265, and many sites are written
   to explicitly use their own specific named domain when sending cookies.


   Cookie parsing and use is opt-in by applications and is not enabled by

   The Common Vulnerabilities and Exposures (CVE) project has assigned the name
   CVE-2014-3613 to this issue.


   The IP address flaw has existed ever since libcurl started to support

   Affected versions: from libcurl 7.1 to and including 7.37.1
   Not affected versions: libcurl >= 7.38.0

   libcurl is used by many applications, but not always advertised as such!


   libcurl 7.38.0 makes sure that when connected to a site specified with a
   literal IP address, only exact matches are considered for cookies.

   A patch for this problem is available at:


   We suggest you take one of the following actions immediately, in order of

   A - Upgrade to curl and libcurl 7.38.0

   B - Apply the patch and rebuild libcurl

   C - Avoid using cookies in your application if you ever use URLs involving
       literal IP addresses.


   It was reported to the curl project on August 15th 2014. We contacted
   distros_at_openwall on September 1st.

   libcurl 7.38.0 was released on September 10th 2014, coordinated with the
   publication of this advisory.


   Reported by Tim Ruehsen. Patch written by Tim Ruehsen.

   Thanks a lot!

List admin:
Received on 2014-09-10