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                           CERT-Renater

               Note d'Information No. 2013/VULN148
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DATE                : 15/04/2013

HARDWARE PLATFORM(S): /

OPERATING SYSTEM(S): Systems running libcurl versions up to and
                              including 7.29.0.

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http://curl.haxx.se/docs/adv_20130412.html
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                       libcurl cookie domain tailmatch
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Project cURL Security Advisory, April 12th 2013
http://curl.haxx.se/docs/security.html


1. VULNERABILITY

  libcurl is vulnerable to a cookie leak vulnerability when doing
requests across domains with matching tails.

  When communicating over HTTP(S) and having libcurl's cookie engine
enabled, libcurl will store and hold cookies for use when subsequent
requests are done to hosts and paths that match those kept cookies. Due
to a bug in the tailmatching function, libcurl could wrongly send
cookies meant for the domain 'ample.com' when communicating with
'example.com'.

  This vulnerability can be used to hijack sessions in targetted attacks
since registering domains using a known domain's name as an ending is
trivial.

  Both curl the command line tool and applications using the libcurl
library are vulnerable.

  There are no known exploits available at this time.

  The Common Vulnerabilities and Exposures (CVE) project has assigned
the name CVE-2013-1944 to this issue.


2. AFFECTED VERSIONS

  Affected versions: all versions to and including 7.29.0
  Not affected versions: curl >= 7.30.0

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


3. THE SOLUTION

  libcurl 7.30.0 implements the function properly and will not send
cookies to sites just because the host names use the same tail.


4. RECOMMENDATIONS

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

  A - Upgrade to curl and libcurl 7.30.0

  B - Apply this patch and rebuild libcurl

      http://curl.haxx.se/curl-tailmatch.patch

  C - Disable use of cookies or HTTP entirely in your application


5. TIME LINE

  Vulnerability found and patched by YAMADA Yasuharu.

  It was reported (publicly) to the curl project on April 9th 2013.

  curl 7.30.0 was released on April 12th 2013, coordinated with the
  publication of this advisory.


6. CREDITS

  Reported and fixed by YAMADA Yasuharu. Thanks a lot!


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