Cisco IOS L2TP Parsing DoS (cisco-sa-20170322-l2tp)

high Nessus Plugin ID 99028


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


According to its self-reported version, the Cisco IOS software running on the remote device is affected by a denial of service vulnerability in its Layer 2 Tunneling Protocol (L2TP) parsing function due to insufficient validation of L2TP packets. An unauthenticated, remote attacker can exploit this issue, via a specially crafted L2TP packet, to cause the device to reload.

Note that this issue only affects devices if the L2TP feature is enabled and the device is configured as an L2TP Version 2 (L2TPv2) or L2TP Version 3 (L2TPv3) endpoint. By default, the L2TP feature is not enabled.


Upgrade to the relevant fixed version referenced in Cisco bug ID CSCuy82078.

See Also

Plugin Details

Severity: High

ID: 99028

File Name: cisco-sa-20170322-l2tp-ios.nasl

Version: 1.9

Type: combined

Family: CISCO

Published: 3/28/2017

Updated: 11/13/2019

Risk Information


Risk Factor: Low

Score: 3.6


Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

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

CVSS Score Source: CVE-2017-3857


Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/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: 3/22/2017

Vulnerability Publication Date: 3/22/2017

Reference Information

CVE: CVE-2017-3857

BID: 97010

CISCO-SA: cisco-sa-20170322-l2tp