The NATS official Rust clients are vulnerable to MitM when using TLS.
A fix for the
nats crate hasn't been released yet. Since the
nats crate is going to be deprecated anyway, consider switching to
>= 0.29 which already fixed this vulnerability.
The common name of the server's TLS certificate is validated against the
hostname provided by the server's plaintext
INFO message during the initial connection setup phase. A MitM proxy can tamper with the
host field's value by substituting it with the common name of a valid certificate it controls, fooling the client into accepting it.
INFO, alters the
hostJSON field and passes the tampered
INFOback to the client
hostwas set to the common name of said certificate
rustlsaccepts the certificate, having verified that the common name matches the attacker-controlled value it was given