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cURL > Docs > Security > libcurl not verifying certs for TLS to IP address / Winssl

libcurl not verifying certs for TLS to IP address / Winssl

          libcurl not verifying certs for TLS to IP address / Winssl
          ==========================================================
 
Project cURL Security Advisory, March 26th 2014
http://curl.haxx.se/docs/security.html
 
1. VULNERABILITY
 
  When asked to do a TLS connection (HTTPS, FTPS, IMAPS, etc) to a URL
  specified with an IP address instead of a name, libcurl would wrongly not
  verify the server's name in the certificate. The signature (whether it was
  signed by a trusted CA) and validity (whether the date was within the
  certificate's lifetime and it was not revoked) verifications were still
  performed.
 
  This is a problem in libcurl built to use the SChannel/Winssl TLS backend.
  SChannel/Winssl is the native library provided by Microsoft Windows.
 
  Only users on Windows can be affected by this. And only if libcurl was built
  to use the native TLS backend library.
 
  The Common Vulnerabilities and Exposures (CVE) project has assigned the name
  CVE-2014-2522 to this issue.
 
2. AFFECTED VERSIONS
 
  This flaw has existed ever since libcurl started to support the
  SChannel/Winssl backend.
 
  Affected versions: from libcurl 7.27.0 to and including 7.35.0
  Not affected versions: libcurl >= 7.36.0
 
  libcurl is used by many applications, but not always advertised as such!
 
3. THE SOLUTION
 
  libcurl 7.36.0 makes sure that all TLS using requests verify the host name
  even if specified as an IP address in the URL.
 
  A patch for this problem is available at:
 
    https://github.com/bagder/curl/commit/63fc8ee7be2b71
 
  The fix was committed to the public source code repository because the full
  security impact wasn't properly realized until after the fact.
 
4. RECOMMENDATIONS
 
  We suggest you take one of the following actions immediately, in order of
  preference:
 
  A - Upgrade to curl and libcurl 7.36.0
 
  B - Apply the patch and rebuild libcurl
 
  C - Rebuild libcurl to use another TLS backend
 
5. TIME LINE
 
  It was discovered by the curl project during late February 2014.
 
  libcurl 7.36.0 was released on March 26th 2014, coordinated with the
  publication of this advisory.
 
6. CREDITS
 
  David Ryskalczyk made us aware of this flaw and wrote the patch.
 
  Marc Hoersken helped coordinate the bug fix.
 
  Thanks a lot!

donate! Page updated March 26, 2014.
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