Cisco Security Advisory
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AV:N/AC:H/Au:N/C:N/I:N/A:C/E:F/RL:OF/RC:C
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A vulnerability in the flow manager code of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause flow manager to hold UDP sessions in its table.
The vulnerability is due to not releasing memory for flows generated by TFTP UDP traffic. An attacker could exploit this vulnerability by either starting a local TFTP transaction from the device, or by requesting a TFTP file operation when the device is configured as a TFTP server. An exploit could allow the attacker to have the Cisco IOS XE software hold the flow manager sessions in a table, decreasing memory and eventually resulting in system instability or a potential system crash.
Cisco has confirmed the vulnerability in a security notice and released software updates.
Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available.
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Customers are advised to consult Cisco bug ID CSCty42686 for the most complete list of affected product versions.
Vulnerable Products
At the time this alert was first published, Cisco IOS XE Software Release 3.4SG(.2) and prior were vulnerable. Later releases of Cisco IOS XE Software may also be vulnerable.Products Confirmed Not Vulnerable
No other Cisco products are currently known to be affected by these vulnerabilities.
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Administrators are advised to apply the appropriate updates
Administrators are advised to allow only trusted users to have network access.
Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.
Administrators are advised to monitor affected systems.
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Cisco customers with active contracts should contact their Cisco support team for assistance in upgrading to a software version that includes fixes for this vulnerability. Cisco customers without contracts may contact the Cisco Technical Assistance Center at 1-800-553-2447 or 1-408-526-7209 or via email at tac@cisco.com for assistance.
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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 Cisco IOS XE Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service condition. Updates are available. NA Final 2013-Dec-03
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