Cisco IOS Software ISDN Q.931 DoS (cisco-sa-iosxe-isdn-q931-dos-67eUZBTf)

medium Nessus Plugin ID 141373
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VPR Score: 4.4


The remote device is missing a vendor-supplied security patch


According to its self-reported version, IOS is affected by a DoS vulnerability in the ISDN subsystem due to insufficient input validation when the ISDN Q.931 messages are processed. An unauthenticated, adjacent attacker could exploit this vulnerability by sending a malicious ISDN Q.931 message to an affected device. A successful exploit could allow the attacker to cause the process to crash, resulting in a DoS condition.

Please see the included Cisco BID and Cisco Security Advisory for more information.


Upgrade to the relevant fixed version referenced in Cisco bug ID CSCvr57760

See Also

Plugin Details

Severity: Medium

ID: 141373

File Name: cisco-sa-iosxe-isdn-q931-dos-67eUZBTf-ios.nasl

Version: 1.11

Type: combined

Family: CISCO

Published: 10/12/2020

Updated: 4/29/2021

Dependencies: cisco_ios_version.nasl

Risk Information

Risk Factor: Medium

VPR Score: 4.4

CVSS Score Source: CVE-2020-3511

CVSS v2.0

Base Score: 6.1

Temporal Score: 4.5

Vector: AV:A/AC:L/Au:N/C:N/I:N/A:C

Temporal Vector: E:U/RL:OF/RC:C

CVSS v3.0

Base Score: 7.4

Temporal Score: 6.4

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

Temporal Vector: E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:cisco:ios

Required KB Items: Host/Cisco/IOS/Version

Exploit Ease: No known exploits are available

Patch Publication Date: 9/24/2020

Vulnerability Publication Date: 9/24/2020

Reference Information

CVE: CVE-2020-3511


CISCO-SA: cisco-sa-iosxe-isdn-q931-dos-67eUZBTf

IAVA: 2020-A-0439

CWE: 20