CVE-2020-3561: 
Cisco Adaptive Security Appliance (ASA) vulnerability analysis and mitigation

A vulnerability (CVE-2020-3561) was discovered in the Clientless SSL VPN (WebVPN) functionality of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software. The vulnerability was disclosed on October 21, 2020, and affects the WebVPN component of these security products (MITRE CVE).

The vulnerability stems from improper input sanitization in the WebVPN component. This security flaw could allow an unauthenticated, remote attacker to perform CRLF (Carriage Return Line Feed) injection attacks by adding arbitrary HTTP headers in the system's responses (MITRE CVE).

If successfully exploited, this vulnerability enables attackers to inject arbitrary HTTP headers into the system's responses and potentially redirect users to malicious websites. The attack requires user interaction, specifically clicking on a crafted link (MITRE CVE).

The vulnerability can be exploited by an unauthenticated, remote attacker by persuading a user of the interface to click on a specially crafted link. The attack vector requires social engineering to be successful (MITRE CVE).