CVE-2020-3561 Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software WebVPN CRLF Injection Vulnerability

Medium 4.7 Published 21 Oct 2020 Updated 13 Nov 2024

Unauthenticated attackers can inject HTTP headers via crafted links, enabling redirects and potential security bypasses in Cisco ASA and FTD WebVPN.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: None listed

What is CVE-2020-3561?

CVE-2020-3561 is a medium-severity vulnerability in Cisco Adaptive Security Appliance, published on 21 Oct 2020. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

A vulnerability in the Clientless SSL VPN (WebVPN) of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to inject arbitrary HTTP headers in the responses of the affected system. The vulnerability is due to improper input sanitization. An attacker could exploit this vulnerability by persuading a user of the interface to click a crafted link. A successful exploit could allow the attacker to conduct a CRLF injection attack, adding arbitrary HTTP headers in the responses of the system and redirecting the user to arbitrary websites.

Weakness: CWE-74, CWE-93

Which versions are affected by CVE-2020-3561?

It affects 3 products.

Products include Cisco Adaptive Security Appliance, Cisco Adaptive Security Appliance Software, Cisco Secure Firewall Threat Defense.

How do I fix CVE-2020-3561?

No fix has been published for CVE-2020-3561 yet. Limit exposure of the affected software until one is available.

Is CVE-2020-3561 being exploited?

There is no known exploitation of CVE-2020-3561 in the wild and no public exploit code.

All Cisco Adaptive Security Appliance vulnerabilities

Sources

Also known as GHSA-pm23-qjx3-gg3f.