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

Medium Nessus Plugin ID 85685


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


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.


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

See Also

Plugin Details

Severity: Medium

ID: 85685

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

Version: 1.12

Type: combined

Family: CISCO

Published: 2015/08/28

Updated: 2019/11/25

Dependencies: 66696

Configuration: Enable paranoid mode

Risk Information

Risk Factor: Medium

CVSS Score Source: CVE-2015-1793

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

CVSS v3.0

Base Score: 6.5

Temporal Score: 5.9

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Temporal Vector: CVSS:3.0/E:P/RL:O/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