CVE-2024-3661 Information

Description

By design the DHCP protocol does not authenticate messages including for example the classless static route option (121). An attacker with the ability to send DHCP messages can manipulate routes to redirect VPN traffic allowing the attacker to read disrupt or possibly modify network traffic that was expected to be protected by the VPN. Many if not most VPN systems based on IP routing are susceptible to such attacks.

Reference

https://datatracker.ietf.org/doc/html/rfc2131#section-7 https://datatracker.ietf.org/doc/html/rfc3442#section-7 https://tunnelvisionbug.com/ https://www.leviathansecurity.com/research/tunnelvision https://news.ycombinator.com/item?id=40279632 https://arstechnica.com/security/2024/05/novel-attack-against-virtually-all-vpn-apps-neuters-their-entire-purpose/ https://krebsonsecurity.com/2024/05/why-your-vpn-may-not-be-as-secure-as-it-claims/ https://issuetracker.google.com/issues/263721377 https://mullvad.net/en/blog/evaluating-the-impact-of-tunnelvision https://www.zscaler.com/blogs/security-research/cve-2024-3661-k-tunnelvision-exposes-vpn-bypass-vulnerability https://lowendtalk.com/discussion/188857/a-rogue-dhcp-server-within-your-network-can-and-will-hijack-your-vpn-traffic https://news.ycombinator.com/item?id=40284111 https://www.agwa.name/blog/post/hardening_openvpn_for_def_con