Cisco IOS XR on ASR 9000 Routers BVI Interface Bugs Let Remote Users Deny Service
SecurityTracker Alert ID: 1032139|
SecurityTracker URL: http://securitytracker.com/id/1032139
(Links to External Site)
Date: Apr 15 2015
Denial of service via network|
Fix Available: Yes Vendor Confirmed: Yes |
A vulnerability was reported in Cisco IOS XR on ASR Routers. A remote user can cause denial of service conditions on the target system.|
A remote user can send specially crafted IPv4 packets through the target device that is configured to route the packets via the bridge-group virtual interface (BVI) to cause the target network processor chip to lockup and eventually reload.
Systems configured to route traffic via the BVI and with the Unicast Reverse Path Forwarding (uRPF), policy-based routing (PBR), quality of service (QoS), or access control list (ACL) features enabled are affected.
Cisco Aggregation Services Routers (ASR) 9000 Series routers with Typhoon-based line cards are affected.
The Cisco ASR 9001 and Cisco ASR 9001-S Routers are affected.
IOS XR prior to version 4.3.0 is not affected.
The vendor has assigned bug ID CSCur62957 to this vulnerability.
A remote user can cause the target network processor chip to lockup and eventually reload.|
The vendor has issued a fix:|
For 4.3.4: asr9k-px-4.3.4.CSCur62957.pie
For 5.1.2: asr9k-px-5.1.2.CSCur62957.pie
For 5.1.3: asr9k-px-5.1.3.CSCur62957.pie
For 5.2.2: asr9k-px-5.2.2.CSCur62957.pie
For 5.3.0: asr9k-px-5.3.0.CSCur62957.pie
The vendor's advisory is available at:
Vendor URL: tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20150415-iosxr (Links to External Site)
Source Message Contents
Subject: Cisco Security Advisory: Cisco IOS XR Software BVI Routed Packet Denial of Service Vulnerability|
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Cisco IOS XR Software BVI Routed Packet Denial of Service Vulnerability
Advisory ID: cisco-sa-20150415-iosxr
For Public Release 2015 April 15 16:00 UTC (GMT)
A vulnerability in the packet-processing code of Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers (ASR) could allow an unauthenticated, remote attacker to cause a lockup and eventual reload of a network processor chip and the line card that is processing traffic. Only Typhoon-based line cards on Cisco ASR 9000 Series Aggregation Services Routers are affected by this vulnerability.
The vulnerability is due to improper processing of packets that are routed via the bridge-group virtual interface (BVI) when any of the following features are configured: Unicast Reverse Path Forwarding (uRPF), policy-based routing (PBR), quality of service (QoS), or access control lists (ACLs). An attacker could exploit this vulnerability by sending IPv4 packets through an affected device that is configured to route them via the BVI interface. A successful exploit could allow the attacker to cause a lockup and eventual reload of a network processor chip and the line card that is processing traffic, leading to a denial of service (DoS) condition.
Cisco has released free software updates that address this vulnerability. There are no workarounds to address this vulnerability.
This advisory is available at the following link:
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