Cisco Security AdvisoryMedium
Advisory ID:
cisco-sa-20160902-ios
First Published:
2016 September 2 12:30 GMT
Last Updated:
2016 September 2 19:38 GMT
Version 1.1:
Workarounds:
Cisco Bug IDs:
CVSS Score:
Base 5.0,
Temporal 4.5
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AV:N/AC:L/Au:N/C:P/I:N/A:N/E:F/RL:W/RC:C
Click Icon to Copy Verbose Score
AV:N/AC:L/Au:N/C:P/I:N/A:N/E:F/RL:W/RC:C
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A vulnerability in the implementation of Point-to-Point Tunneling Protocol (PPTP) server functionality in Cisco IOS Software could allow an unauthenticated, remote attacker to access data from a packet buffer that was previously used.
The vulnerability is due to the use of a previously used packet buffer whose content was not cleared from memory. An attacker could exploit this vulnerability by sending a PPTP connection request to device that is running a vulnerable release of the affected software and is configured for PPTP server functionality. A successful exploit could allow the attacker to access up to 63 bytes of memory that were previously used for a packet and were either destined to the device or generated by the device. An exploit would not allow the attacker to access packet data from transit traffic. In addition, an exploit would not allow the attacker to access arbitrary memory locations that the attacker chooses.
Cisco has not released software updates that address this vulnerability. There is a workaround that addresses this vulnerability.
This advisory is available at the following link:
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20160902-ios
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Vulnerable Products
For information about software releases that are affected by or fix this vulnerability, refer to Cisco bug CSCvb16274.Products Confirmed Not Vulnerable
No other Cisco products are currently known to be affected by this vulnerability.
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To work around this vulnerability, administrators can configure a 64-character local name for any virtual private dialup network (VPDN) group that is enabled for PPTP functionality. This will prevent content from being leaked from memory. The local name must be exactly 64 characters in length.
The following example shows a VPDN group that has a local name consisting of 64 hash marks:
vpdn-group 1 accept-dialin protocol pptp virtual-template 1 local name ################################################################
For more information about the local name VPDN command, see the Cisco IOS VPDN Command Reference.
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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 regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories and Alerts page, 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 1.1 Added a link to Cisco bug CSCvb16274. Vulnerable Products Final 2016-September-02 1.0 Initial public release. — Final 2016-September-02
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