Cisco Security Advisory
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AV:N/AC:M/Au:N/C:P/I:N/A:N/E:F/RL:OF/RC:C
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A vulnerability in the Cisco Adaptive Security Appliance (ASA) Software implementation of access control list (ACL) permit and deny filters for ICMP echo reply messages could allow an unauthenticated, remote attacker to bypass ACL configurations for an affected device. ICMP traffic that should be denied may instead be allowed through an affected device.
The vulnerability is due to the implementation of ACL-based filters for ICMP echo requests and the range of ICMP echo request subtypes. An attacker could exploit this vulnerability by sending ICMP echo request traffic to an affected device. A successful exploit could allow the attacker to bypass ACL configurations for the device, which could allow traffic that should be denied to instead be allowed through the device.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
This advisory is available at the following link: https://sec.cloudapps.cisco.comsecurity/center/content/CiscoSecurityAdvisory/cisco-sa-20160711-asa
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Vulnerable Products
Cisco Adaptive Security Appliance (ASA) Software Releases 8.2 up to the first fixed software release are vulnerable. This vulnerability is fixed in software versions 9.4.3.3, 9.5.2.10, and 9.6.1.5. Please refer to the "Fixed Software" section for additional information about fixed releases.
An ASA is vulnerable if it is configured with ACLs that allow ICMP echo requests. An example of the vulnerable configuration follows:
access-list my-list extended permit icmp any any echo-reply 0 log interval 1
Firepower Threat Defense (FTD) is also vulnerable.Products Confirmed Not Vulnerable
No other Cisco products are currently known to be affected by this vulnerability.
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There are no workarounds that address this vulnerability.
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Cisco provides information about fixed software in Cisco bugs, which are accessible through the Cisco Bug Search Tool.
When considering software upgrades, customers are advised to consult the Cisco Security Advisories and Responses archive at http://www.cisco.com/go/psirt and review subsequent advisories to determine exposure and a complete upgrade solution.
In all cases, customers should ensure that the devices to upgrade contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.
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The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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Show LessVersion Description Section Status Date 1.1 Clarified vulnerable products. Added instructions for identifying a vulnerable configuration. Vulnerable Products Final 2016-July-21 1.0 Initial public release. — Final 2016-July-11
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