Cisco IOS Software Secure Shell DoS (cisco-sa-ssh-dos-Un22sd2A)

high Nessus Plugin ID 137141

Synopsis

The remote device is missing a vendor-supplied security patch

Description

According to its self-reported version, IOS is affected by a vulnerability in the Secure Shell (SSH) server code due to an internal state not being represented correctly in the SSH state machine, which leads to an unexpected behavior.
An authenticated, remote attacker can exploit this, by creating an SSH connection and using a specific traffic pattern that causes an error condition within that connection. A successful exploit can cause the affected device to reload, resulting in a denial of service (DoS) condition.

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

Solution

Upgrade to the relevant fixed version referenced in Cisco bug ID CSCvp79333

See Also

http://www.nessus.org/u?08fa240a

http://tools.cisco.com/security/center/viewErp.x?alertId=ERP-73388

https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvp79333

Plugin Details

Severity: High

ID: 137141

File Name: cisco-sa-ssh-dos-Un22sd2A-ios.nasl

Version: 1.12

Type: combined

Family: CISCO

Published: 6/5/2020

Updated: 6/3/2021

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5

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

CVSS Score Source: CVE-2020-3200

CVSS v3

Risk Factor: High

Base Score: 7.7

Temporal Score: 6.7

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

Temporal Vector: CVSS:3.0/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: 6/3/2020

Vulnerability Publication Date: 6/3/2020

Reference Information

CVE: CVE-2020-3200

CWE: 371

CISCO-SA: cisco-sa-ssh-dos-Un22sd2A

IAVA: 2020-A-0239-S

CISCO-BUG-ID: CSCvp79333