FreeBSD VuXML: Documenting security issues in FreeBSD and the FreeBSD Ports Collection

cURL library -- cert name check ignore with GnuTLS

Affected packages
7.21.4 <= curl < 7.33.0_2


VuXML ID 4e1f4abc-6837-11e3-9cda-3c970e169bc2
Discovery 2013-12-17
Entry 2013-12-18

cURL project reports:

libcurl is vulnerable to a case of missing out the checking of the certificate CN or SAN name field when the digital signature verification is turned off.

libcurl offers two separate and independent options for verifying a server's TLS certificate. CURLOPT_SSL_VERIFYPEER and CURLOPT_SSL_VERIFYHOST. The first one tells libcurl to verify the trust chain using a CA cert bundle, while the second tells libcurl to make sure that the name fields in the server certificate meets the criteria. Both options are enabled by default.

This flaw had the effect that when an application disabled CURLOPT_SSL_VERIFYPEER, libcurl mistakenly also skipped the CURLOPT_SSL_VERIFYHOST check. Applications can disable CURLOPT_SSL_VERIFYPEER and still achieve security by doing the check on its own using other means.

The curl command line tool is not affected by this problem as it either enables both options or disables both at the same time.


CVE Name CVE-2013-6422