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AUSCERT External Security Bulletin Redistribution
ESB-2016.1610
Cisco Web Security Appliance Native FTP Denial of Service Vulnerability
28 June 2016
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AusCERT Security Bulletin Summary
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Product: Cisco Web Security Appliance
Publisher: Cisco Systems
Operating System: Cisco
Impact/Access: Denial of Service -- Remote/Unauthenticated
Resolution: Patch/Upgrade
CVE Names: CVE-2016-1440
Original Bulletin:
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160627-wsa
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Cisco Security Advisory
Cisco Web Security Appliance Native FTP Denial of Service Vulnerability
Medium
Advisory ID:
cisco-sa-20160627-wsa
Published:
2016 June 27 18:40 GMT
Version 1.0:
Final
CVSS Score:
Base - 5.0
Workarounds:
No workarounds available
Cisco Bug IDs:
CSCuy43468
CVE-2016-1440
CWE-399
Summary
A vulnerability in the native pass-through FTP functionality of the Cisco Web
Security Appliance (WSA) could allow an unauthenticated, remote attacker to
cause a partial denial of service (DoS) condition due to high CPU utilization.
The vulnerability is due to how the FTP client terminates the FTP control
connection when the data transfer is complete. An attacker could exploit this
vulnerability by initiating FTP connections through the WSA. An exploit could
allow the attacker to cause high CPU utilization of the Cisco WSA proxy
process, causing a partial DoS condition. Successful exploitation depends on
the FTP client the attacker uses and how that FTP client closes the FTP
control connection.
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:
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160627-wsa
Affected Products
Vulnerable Products
All Cisco WSA releases prior to the first fixed release are vulnerable.
Products Confirmed Not Vulnerable
No other Cisco products are currently known to be affected by this
vulnerability.
Workarounds
Workarounds that address this vulnerability are not available.
Fixed Software
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 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.
Exploitation and Public Announcements
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.
URL
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160627-wsa
Revision History
Version Description Section Status Date
1.0 Initial public release. - Final 2016-June-27
Legal Disclaimer
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.
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