Cisco Secure Client Carriage Return Line Feed Injection Vulnerability [CVE-2024-20337]

CVE number – CVE-2024-20337

This vulnerability affects the following Cisco products if they are running a vulnerable release of Cisco Secure Client and the VPN headend is configured with the SAML External Browser feature:

• Secure Client for Linux
• Secure Client for macOS
• Secure Client for Windows

A vulnerability in the SAML authentication process of Cisco Secure Client could allow an unauthenticated, remote attacker to conduct a carriage return line feed (CRLF) injection attack against a user.

This vulnerability is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by persuading a user to click a crafted link while establishing a VPN session.

A successful exploit could allow the attacker to execute arbitrary script code in the browser or access sensitive, browser-based information, including a valid SAML token.

The attacker could then use the token to establish a remote access VPN session with the privileges of the affected user.

Individual hosts and services behind the VPN headend would still need additional credentials for successful access.

Cisco has released software updates that address this vulnerability.

There are no workarounds that address this vulnerability.

This advisory is available at the following link:
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-secure-client-crlf-W43V4G7