CVE-2020-3408 Cisco IOS and IOS XE Software Split DNS Denial of Service Vulnerability

High 8.6 Published 24 Sep 2020 Updated 13 Nov 2024

Remote attackers can cause a denial of service on Cisco IOS devices by exploiting a regex timeout in the Split DNS feature.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2020-3408?

CVE-2020-3408 is a high-severity denial of service vulnerability in Cisco Ios, published on 24 Sep 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A vulnerability in the Split DNS feature of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerability occurs because the regular expression (regex) engine that is used with the Split DNS feature of affected releases may time out when it processes the DNS name list configuration. An attacker could exploit this vulnerability by trying to resolve an address or hostname that the affected device handles. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

Weakness: CWE-400, CWE-185

Which versions are affected by CVE-2020-3408?

It affects 2 products.

Products include Cisco Ios, Cisco Ios Xe.

How do I fix CVE-2020-3408?

No fix has been published for CVE-2020-3408 yet. Limit exposure of the affected software until one is available.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2020-3408 being exploited?

There is no known exploitation of CVE-2020-3408 in the wild and no public exploit code.

All Cisco Ios vulnerabilities

Sources

Also known as GHSA-53cq-v8h5-f4v2.