Advisories for Golang/Github.com/Jpillora/Chisel package

Authenticated chisel clients can bypass –authfile ACL restrictions and tunnel traffic to arbitrary destinations reachable from the server. The ACL is enforced only during the initial handshake against declared remotes, but never on subsequent SSH channels that carry actual traffic. A malicious client authenticates with a permitted remote, then opens channels to any host:port it wants.

The Chisel server doesn't ever read the documented AUTH environment variable used to set credentials, which allows any unauthenticated user to connect, even if credentials were set. This advisory is a formalization of a report sent to the maintainer via email.