CVE-2020-3449: Cisco IOS XR Software Additional Paths Denial of Service Vulnerability
First published: Mon Aug 17 2020(Updated: )
A vulnerability in the Border Gateway Protocol (BGP) additional paths feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to prevent authorized users from monitoring the BGP status and cause the BGP process to stop processing new updates, resulting in a denial of service (DOS) condition. The vulnerability is due to an incorrect calculation of lexicographical order when displaying additional path information within Cisco IOS XR Software, which causes an infinite loop. An attacker could exploit this vulnerability by sending a specific BGP update from a BGP neighbor peer session of an affected device; an authorized user must then issue a show bgp command for the vulnerability to be exploited. A successful exploit could allow the attacker to prevent authorized users from properly monitoring the BGP status and prevent BGP from processing new updates, resulting in outdated information in the routing and forwarding tables.
Credit: ykramarz@cisco.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Cisco IOS XR | <7.1.2 | |
| Cisco IOS XR | >=7.2.0<7.2.1 | |
| Cisco IOS XR | >=7.3.0<7.3.1 |
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Reference Links
Frequently Asked Questions
What is CVE-2020-3449?
CVE-2020-3449 is a vulnerability in the Border Gateway Protocol (BGP) additional paths feature of Cisco IOS XR Software that could allow an unauthenticated, remote attacker to cause a denial of service.
How does CVE-2020-3449 affect Cisco IOS XR Software?
CVE-2020-3449 affects Cisco IOS XR Software versions 7.1.2 up to (but not including) 7.3.2, allowing an attacker to stop the BGP process from processing new updates and prevent authorized users from monitoring the BGP status.
What is the severity of CVE-2020-3449?
CVE-2020-3449 has a severity rating of 4.3, which is considered medium.
How can an attacker exploit CVE-2020-3449?
An attacker can exploit CVE-2020-3449 by sending specially crafted BGP update messages to the targeted device, causing the BGP process to stop processing new updates and resulting in a denial of service.
Is there a patch or update available to fix CVE-2020-3449?
Yes, Cisco has released a software update to address the vulnerability. Users are advised to upgrade to Cisco IOS XR Software version 7.3.2 or later to mitigate the risk of exploitation.
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