Cisco ASA SNMP Packet Handling RCE (CSCva92151) (EXTRABACON)

high Nessus Plugin ID 93113
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Synopsis

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

Description

According to its banner and configuration, the version of the remote Cisco Adaptive Security Appliance (ASA) device is affected by a remote code execution vulnerability, known as EXTRABACON, in the Simple Network Management Protocol (SNMP) code due to a buffer overflow condition. An authenticated, remote attacker can exploit this, via specially crafted IPv4 SNMP packets, to cause a denial of service condition or the execution of arbitrary code. Note that an attacker must know the SNMP community string in order to exploit the vulnerability.

EXTRABACON is one of multiple Equation Group vulnerabilities and exploits disclosed on 2016/08/14 by a group known as the Shadow Brokers.

Solution

Upgrade to the relevant fixed version referenced in Cisco bug ID CSCva92151. Alternatively, as a workaround, change the SNMP community string, and only allow trusted users to have SNMP access.

Additionally, administrators can monitor affected systems using the 'snmp-server' host command.

See Also

http://www.nessus.org/u?4c7e0cf3

https://blogs.cisco.com/security/shadow-brokers

http://www.nessus.org/u?158a2c56

https://bst.cloudapps.cisco.com/bugsearch/bug/CSCva92151

Plugin Details

Severity: High

ID: 93113

File Name: cisco-sn-CSCva92151-asa.nasl

Version: 1.14

Type: local

Family: CISCO

Published: 8/25/2016

Updated: 11/14/2019

Dependencies: ssh_get_info.nasl

Risk Information

CVSS Score Source: CVE-2016-6366

VPR

Risk Factor: High

Score: 7.4

CVSS v2

Risk Factor: High

Base Score: 8.5

Temporal Score: 7

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

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

CVSS v3

Risk Factor: High

Base Score: 8.8

Temporal Score: 8.2

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

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

Vulnerability Information

CPE: cpe:2.3:a:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*

Required KB Items: Host/Cisco/ASA

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 8/17/2016

Vulnerability Publication Date: 8/14/2016

Exploitable With

CANVAS (CANVAS)

Core Impact

Reference Information

CVE: CVE-2016-6366

BID: 92521

CISCO-BUG-ID: CSCva92151

CISCO-SA: cisco-sa-20160817-asa-snmp

EDB-ID: 40258