CVE-2021-22161 Explained : Impact and Mitigation
Discover the impact of CVE-2021-22161 affecting OpenWrt 19.07.x versions. Learn about the routing loop issue with IPv6, affected systems, and mitigation steps.
A routing loop vulnerability in OpenWrt 19.07.x before 19.07.7 involving IPv6 can lead to excessive network traffic. This impacts the netifd and odhcp6c packages.
Understanding CVE-2021-22161
This CVE highlights a critical issue within OpenWrt 19.07.x versions that could potentially disrupt network traffic due to a routing loop problem related to IPv6.
What is CVE-2021-22161?
The vulnerability arises in OpenWrt 19.07.x prior to version 19.07.7 when utilizing IPv6, causing a routing loop that results in increased network traffic between the impacted device and the upstream ISP's router.
The Impact of CVE-2021-22161
The vulnerability can lead to a significant rise in network traffic, potentially causing disruption between the affected device and the ISP's router, affecting the overall network performance.
Technical Details of CVE-2021-22161
This section delves into the specifics of the vulnerability, including description, affected systems and versions, and exploitation mechanism.
Vulnerability Description
The issue occurs when a link prefix route points to a point-to-point link, an IPv6 address falls within the prefix but is not local, and a router advertisement contains a global unique IPv6 prefix with the on-link flag set.
Affected Systems and Versions
OpenWrt 19.07.x versions before 19.07.7 are impacted by this vulnerability, particularly affecting the netifd and odhcp6c packages.
Exploitation Mechanism
Exploiting this vulnerability involves triggering a routing loop using specific conditions related to IPv6 that lead to excessive network traffic.
Mitigation and Prevention
It is crucial to take immediate steps to address the CVE and implement security measures to prevent similar issues in the future.
Immediate Steps to Take
Users should update their OpenWrt installations to version 19.07.7 or newer to mitigate the vulnerability. Network monitoring can help detect any unusual traffic patterns.
Long-Term Security Practices
Regularly updating firmware and implementing network security best practices can enhance overall system security and reduce the risk of similar vulnerabilities.
Patching and Updates
OpenWrt users should stay informed about security advisories and promptly apply patches released by OpenWrt to address critical vulnerabilities like CVE-2021-22161.