Multiple Vendor HMAC Authentication SNMPv3 Authentication Bypass

critical Nessus Plugin ID 40449
New! Vulnerability Priority Rating (VPR)

Tenable calculates a dynamic VPR for every vulnerability. VPR combines vulnerability information with threat intelligence and machine learning algorithms to predict which vulnerabilities are most likely to be exploited in attacks. Read more about what VPR is and how it is different from CVSS.

VPR Score: 7.4


The SNMP server running on this host is affected by an authentication bypass vulnerability.


SNMPv3 HMAC verification relies on the client to specify the HMAC length. This makes it possible for remote attackers to bypass SNMP authentication via repeated attempts with a HMAC length value of 1, which causes only the first byte of the authentication hash to be checked.

This issue affects SNMP implementations from multiple vendors.


This vulnerability affects multiple products from multiple vendors. Check with your vendor for the appropriate solution.

See Also

Plugin Details

Severity: Critical

ID: 40449

File Name: snmpv3_authentication_bypass.nasl

Version: 1.22

Type: remote

Family: SNMP

Published: 7/31/2009

Updated: 7/30/2018

Dependencies: 11153

Risk Information

Risk Factor: Critical

VPR Score: 7.4

CVSS v2.0

Base Score: 10

Temporal Score: 8.3

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

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

CVSS v3.0

Base Score: 9.8

Temporal Score: 9.1

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

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

Vulnerability Information

Required KB Items: SNMP/v3/username, SNMP/v3/Supported

Exploit Available: true

Exploit Ease: Exploits are available

Exploited by Nessus: true

Patch Publication Date: 6/9/2008

Vulnerability Publication Date: 5/31/2008

Exploitable With

CANVAS (D2ExploitPack)

Reference Information

CVE: CVE-2008-0960

BID: 29623

CERT: 878044

EDB-ID: 5790

CWE: 287