Cisco Security Advisory
Cisco Adaptive Security Appliance XML Parser Denial of Service Vulnerability
Click Icon to Copy Verbose Score
AV:N/AC:L/Au:S/C:N/I:N/A:C/E:F/RL:OF/RC:C
-
A vulnerability in XML parser code of Cisco Adaptive Security Appliance Software could allow an authenticated, remote attacker to cause system instability or a reload of the affected system.
The vulnerability is due to insufficient hardening of the XML parser configuration. An attacker could exploit this vulnerability in multiple ways by utilizing a malicious file. An attacker with administrative privileges could exploit this by uploading a malicious XML file on the system and trigger the XML code to parse the malicious file. Additionally, an attacker with Clienteles SSL VPN access could exploit this vulnerability by sending a crafted XML file. An exploit would allow the attacker to crash the XML parser process, which could cause system instability, memory exhaustion, and in some cases lead to a reload of the affected system.
Cisco has released software updates that address this vulnerability. Workarounds that address this vulnerability are not available.
This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160517-asa-xml
-
If the attacker has administrative privileges, the exposure does not depend on the actual configuration.
In the scenario where the attacker has access to a Clientless SSL VPN session, Cisco Adaptive Security Appliance software is vulnerable if the Clientless SSL VPN feature and File Access (also known as Browse Networks) via Common Internet File System (CIFS) or FTP is allowed.
-
Workarounds are not available.
-
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 be upgraded 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.
Customers should upgrade to an appropriate release as indicated in the following table.
In the table, the left column lists major releases of Cisco ASA Software. The right column indicates whether a major release is affected by the vulnerability described in this advisory and the first release that includes the fix for this vulnerability.
Cisco ASA Major Release First Fixed Release Prior to 9.0
Affected. Migrate to 9.1(7.6) or later
9.0
Affected. Migrate to 9.1(7.6) or later
9.1 9.1(7.6)
9.2 9.2(4.8) 9.3 9.3(3.8) 9.4 9.4(2.6)
9.5
9.5(2.6) 9.6
Not affected
-
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.
-
This vulnerability was found during internal security tests.
-
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.
-
Show LessVersion Description Section Status Date 1.0 Initial public release. - Final 2016-May-17
-
THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.
A standalone copy or paraphrase of the text of this document that omits the distribution URL is an uncontrolled copy and may lack important information or contain factual errors. The information in this document is intended for end users of Cisco products.