CVE-2021-3125 : What You Need to Know

A vulnerability in TP-Link devices can lead to a routing loop when using IPv6, causing excessive network traffic between the device and its ISP's router.

Understanding CVE-2021-3125

This CVE impacts TP-Link devices running specific firmware versions, potentially resulting in a network traffic amplification issue.

What is CVE-2021-3125?

The vulnerability in TP-Link TL-XDR series routers can trigger a routing loop, generating high network traffic between the device and the upstream ISP's router when IPv6 is utilized.

The Impact of CVE-2021-3125

The exploitation of this vulnerability could lead to a Denial of Service (DoS) condition due to the excessive network traffic, affecting network performance and availability.

Technical Details of CVE-2021-3125

This section describes the specifics of the vulnerability.

Vulnerability Description

The issue arises when a link prefix route on the affected device points to a point-to-point link, leading to a routing loop with upstream routers via IPv6.

Affected Systems and Versions

TP-Link TL-XDR3230 < 1.0.12, TL-XDR1850 < 1.0.9, TL-XDR1860 < 1.0.14, TL-XDR3250 < 1.0.2, TL-XDR6060 Turbo < 1.1.8, TL-XDR5430 < 1.0.11, and potentially other models are vulnerable.

Exploitation Mechanism

This vulnerability is exploited by leveraging IPv6 traffic to create a routing loop, resulting in the excessive flow of network packets between the affected device and its ISP's router.

Mitigation and Prevention

Learn how to address and prevent CVE-2021-3125.

Immediate Steps to Take

Update the firmware of TP-Link devices to the latest versions, avoid using IPv6 where possible, and monitor network traffic for anomalies.

Long-Term Security Practices

Regularly check for firmware updates from TP-Link, implement network segmentation, and apply access control lists to prevent unauthorized IPv6 traffic.

Patching and Updates

Apply patches released by TP-Link promptly to fix the vulnerability and enhance the security posture of the affected devices.