Cisco Security Advisory
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AV:A/AC:M/Au:N/C:N/I:N/A:C/E:F/RL:OF/RC:C
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A vulnerability in flow control processing of Cisco IOS XR Software for Cisco ASR 9000 Series Routers could allow an unauthenticated, adjacent attacker to cause a Network Processing Unit (NPU) chip reset and potentially a reload of the affected line card.
The vulnerability is due to improper processing of crafted IEEE 802.3x flow control pause frames. An attacker could exploit this vulnerability by sending a number of crafted IEEE 802.3x flow control pause frames to an affected device. An exploit could allow the attacker to cause an NPU chip reset and potentially a reload of the affected line card.
Cisco has confirmed the vulnerability and released software updates.
To exploit this vulnerability an attacker must have access to the same broadcast or collision domain as the targeted device. This access requirement decreases the likelihood of a successful exploit.
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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Cisco has released bug ID CSCut19959 for registered users, which contains additional details and an up-to-date list of affected product versions.
Vulnerable Products
At the time this alert was first published, Cisco ASR 9000 Series Aggregation Services Routers running Cisco IOS XR Software release 5.3.1 was vulnerable. Later releases of Cisco IOS XR 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 can obtain updates through the Software Center at the following link: Cisco. Cisco customers without contracts can obtain upgrades by contacting the Cisco Technical Assistance Center at 1-800-553-2447 or 1-408-526-7209 or via email at tac@cisco.com.
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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 Release NA Final 2015-Jun-22
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