Description
An issue discovered in OpenWrt 18.06, 19.07, 21.02, 22.03, and beyond allows off-path attackers to hijack TCP sessions, which could lead to a denial of service, impersonating the client to the server (e.g., for access to files over FTP), and impersonating the server to the client (e.g., to deliver false information from a finance website). This occurs because nf_conntrack_tcp_no_window_check is true by default.
References
- https://openwrt.org/docs/guide-developer/security
- https://www.ndss-symposium.org/ndss-paper/exploiting-sequence-number-leakage-tcp-hijacking-in-nat-enabled-wi-fi-networks/
- https://blog.apnic.net/2024/06/18/off-path-tcp-hijacking-in-nat-enabled-wi-fi-networks/
- https://news.ycombinator.com/item?id=40723150