Cisco IOS Denilal of Service (DoS) attack attempt

Critical Nessus Network Monitor Plugin ID 700129


The remote host is running a version of Cisco IOS that is being targeted by a Denial of Service attack vector.


Versions of Cisco a flaw that is triggered when handling Cluster Management Protocol-specific Telnet options while establishing a Telnet session on a device which accepts Telnet connections. This may allow a remote attacker to potentially execute arbitrary code or cause a DoS.


Disabling the Telnet protocol as an allowed protocol for incoming connections would eliminate the exploit vector. Disabling Telnet and using SSH is recommended by Cisco.

See Also

Plugin Details

Severity: Critical

ID: 700129

Family: Generic

Published: 2017/06/06

Updated: 2019/03/06

Nessus ID: 97991, 103783

Risk Information

Risk Factor: Critical

CVSS v2.0

Base Score: 10

Temporal Score: 8.7

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

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

CVSS v3.0

Base Score: 9.8

Temporal Score: 9.3

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

Temporal Vector: CVSS:3.0/E:X/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:cisco:ios

Patch Publication Date: 2017/04/21

Vulnerability Publication Date: 2017/03/17

Reference Information

CVE: CVE-2017-3881

BID: 96960