Remote code execution in Cisco ASA Appliances

Published: 2016-08-18 | Updated: 2017-03-24
Severity Critical
Patch available YES
Number of vulnerabilities 1
CVE ID CVE-2016-6366
Exploitation vector Network
Public exploit This vulnerability is being exploited in the wild.
Vulnerable software Cisco ASA 5500 Subscribe
Cisco ASA 5580
Cisco Catalyst 6500 Series ASA Services Module
Cisco ASA 5500-X Series
Cisco ASA 1000V Cloud Firewall
Cisco ASA Series
Vendor Cisco Systems, Inc

Security Advisory

This security advisory describes one critical risk vulnerability.

1) SNMP remote code execution

Severity: Critical

CVSSv3: 9.2 [CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:F/RL:O/RC:C] [PCI]

CVE-ID: CVE-2016-6366

CWE-ID: CWE-119 - Improper Restriction of Operations within the Bounds of a Memory Buffer


The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error when handling SNMP packets. A remote attacker with knowledge of SNMP community string can cause buffer overflow and cause the target device to reload or execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in full compromise of affected system.

The following models of CISCO ASA appliances are affected:

  • Cisco ASA 5500 Series Adaptive Security Appliances
  • Cisco ASA 5500-X Series Next-Generation Firewalls
  • Cisco ASA Services Module for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers
  • Cisco ASA 1000V Cloud Firewall
  • Cisco Adaptive Security Virtual Appliance (ASAv)
  • Cisco Firepower 9300 ASA Security Module
  • Cisco PIX Firewalls
  • Cisco Firewall Services Module (FWSM)

Note: this is a zero-day vulnerability, discovered after security breach of The Equation Group. The exploit code for this vulnerability was publicly exposed and is referred as EXTRABACON Exploit.


Install patches from vendor's website.

Vulnerable software versions

Cisco ASA 5500: 7.2(5), 8.0(5), 8.2(x), 8.3(x), 8.4(x)

Cisco ASA 5580: 8.1(2)

Cisco Catalyst 6500 Series ASA Services Module: -

Cisco ASA 5500-X Series: 8.6(x)

Cisco ASA 1000V Cloud Firewall : 8.7(1)

Cisco ASA Series: 9.0(x), 9.1(x), 9.2(x), 9.3(x), 9.4(x), 9.5(x), 9.6(x)

CPE External links

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, a fully functional exploit for this vulnerability is available.