#VU33155 Improper Certificate Validation in cURL - CVE-2017-7468

Vulnerability identifier: #VU33155

Vulnerability risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2017-7468

CWE-ID: CWE-295

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
cURL
Client/Desktop applications / Other client software

Vendor: curl.haxx.se

Description

The vulnerability allows a remote non-authenticated attacker to manipulate data.

In curl and libcurl 7.52.0 to and including 7.53.1, libcurl would attempt to resume a TLS session even if the client certificate had changed. That is unacceptable since a server by specification is allowed to skip the client certificate check on resume, and may instead use the old identity which was established by the previous certificate (or no certificate). libcurl supports by default the use of TLS session id/ticket to resume previous TLS sessions to speed up subsequent TLS handshakes. They are used when for any reason an existing TLS connection couldn't be kept alive to make the next handshake faster. This flaw is a regression and identical to CVE-2016-5419 reported on August 3rd 2016, but affecting a different version range.

Mitigation
Install update from vendor's website.

Vulnerable software versions

cURL: 7.52.0

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External links
https://www.securityfocus.com/bid/97962
https://www.securitytracker.com/id/1038341
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2017-7468
https://curl.haxx.se/docs/adv_20170419.html
https://security.gentoo.org/glsa/201709-14

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.