#VU82377 Race condition in OpenSSL - CVE-2015-3216

Vulnerability identifier: #VU82377

Vulnerability risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2015-3216

CWE-ID: CWE-362

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
OpenSSL
Server applications / Encryption software

Vendor: OpenSSL Software Foundation

Description

The vulnerability allows a local user to perform a denial of service attack.

The vulnerability exists due to a race condition in a certain Red Hat patch to the PRNG lock implementation in the ssleay_rand_bytes function in OpenSSL. A local user can exploit the race and cause a denial of service (application crash) by establishing many TLS sessions to a multithreaded server, leading to use of a negative value for a certain length field.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

OpenSSL: 1.0.1e-25.el7

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External links
https://lists.opensuse.org/opensuse-security-announce/2015-06/msg00023.html
https://lists.opensuse.org/opensuse-security-announce/2015-06/msg00024.html
https://lists.opensuse.org/opensuse-security-announce/2015-06/msg00026.html
https://lists.opensuse.org/opensuse-security-announce/2015-07/msg00004.html
https://lists.opensuse.org/opensuse-security-announce/2015-07/msg00006.html
https://rhn.redhat.com/errata/RHSA-2015-1115.html
https://rhn.redhat.com/errata/RHSA-2016-2957.html
https://www.securityfocus.com/bid/75219
https://www.securitytracker.com/id/1032587
https://bugzilla.redhat.com/show_bug.cgi?id=1225994

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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.