Cisco Virtual Security Gateway OpenSSL Alternative Certificate Validation Bypass (cisco-sa-20150710-openssl)

Medium Nessus Plugin ID 85685

Synopsis

The remote device is missing a vendor-supplied security patch.

Description

The remote Cisco Virtual Security Gateway device is affected by a certificate validation bypass vulnerability in the bundled OpenSSL library due to a flaw in the X509_verify_cert() function in x509_vfy.c that is triggered when locating alternate certificate chains in cases where the first attempt to build such a chain fails. A remote attacker can exploit this, by using a valid leaf certificate as a certificate authority (CA), to issue invalid certificates that will bypass authentication.

Solution

Upgrade to the relevant fixed version referenced in Cisco bug ID CSCuv26137.

See Also

http://www.nessus.org/u?3b4e4a60

https://tools.cisco.com/bugsearch/bug/CSCuv26137

https://www.openssl.org/news/secadv/20150709.txt

Plugin Details

Severity: Medium

ID: 85685

File Name: cisco-sa-20150710-openssl-VSG.nasl

Version: 1.9

Type: local

Family: CISCO

Published: 2015/08/28

Updated: 2018/11/15

Dependencies: 66696

Configuration: Enable paranoid mode

Risk Information

Risk Factor: Medium

CVSS v2.0

Base Score: 6.4

Temporal Score: 5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:N

Temporal Vector: CVSS2#E:POC/RL:OF/RC:C

Vulnerability Information

CPE: cpe:/o:cisco:nx-os

Required KB Items: Host/Cisco/NX-OS/Version, Settings/ParanoidReport

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 2015/10/31

Vulnerability Publication Date: 2014/07/09

Reference Information

CVE: CVE-2015-1793

BID: 75652

CISCO-SA: cisco-sa-20150710-openssl

CISCO-BUG-ID: CSCuv26137