Cisco Security Advisory
Cisco AsyncOS File Transfer Protocol Denial of Service Vulnerability
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AV:N/AC:M/Au:N/C:N/I:N/A:P/E:F/RL:U/RC:C
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A vulnerability in the local File Transfer Protocol (FTP) service on the Cisco AsyncOS for Email Security Appliance (ESA), Web Security Appliance (WSA), and Content Security Management Appliance (SMA) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.
The vulnerability is due to lack of throttling of FTP connections. An attacker could exploit this vulnerability by sending a flood of FTP traffic to the local FTP service on the targeted device. An exploit could allow the attacker to cause a DoS condition.
CONDITION(s):
The local FTP service is enabled. This is not the default configuration.
To check if local FTP service is enabled, the administrator can use either the GUI or command-line interface (CLI).
1. On the GUI, navigate to Network -> IP Interfaces, click the name of the interface, and in the Services section, check if the FTP service is enabled.
2. For the CLI, the parameter “Do you want to enable FTP on this interface?” would be set to Yes.
Cisco has not released software updates that address this vulnerability. Workarounds that mitigate this vulnerability are not available.
This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160928-aos
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Vulnerable Products
The following Cisco products are affected:
- Cisco Email Security Appliance (ESA)
- Cisco Content Security Management Appliance (SMA)
- Cisco Web Security Appliance (WSA)
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 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.
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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 1.0 Initial public release - Final 2016-September-28
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