Frequent Keepalive Timeouts

[uHACsTx]

Description When establishing a double pivot, I frequently receive a yamux EOF error, which manifests in a timeout and a dead or stopped connection. Sometimes the agent just closes, but sometimes ligolo has to be restarted, including the proxy, to make it work again.

Reproducing the Error Steps to reproduce the behavior:

• Start the proxy with ./proxy -selfcert
• Create the ligolo interface, set it up and create a route to the target network
• Connect an agent from a remote machine
• Create a listener in this session
• Create a second interface, set it up and add a route to the second internal target network
• Connect an agent from an internal host
• Wait or produce traffic

Expected behavior The connection should not stop.

Screenshots

Proxy information:

• OS: [Recent Arch Linux]
• Architecture [amd64]
• Version [ligolo-0.5.2] (A connection was not even possible with newer agents due to this error)

Agent information:

• OS: [Ubuntu Linux, Windows Server 2019]
• Architecture [amd64]
• Version [ligolo-0.5.2] (A connection was not even possible with newer agents due to this error)

Additional context I was using the agent in the CPTS exam. The network connection might have been slow.

[nicocha30]

"Keep Alive Timeout" errors are mainly caused by an unstable network or a loss of TCP connection. The latest version of Ligolo-ng (v0.7), still in alpha, supports automatic recovery of tunnels and listeners. You can run the agent with the -retry option to automatically retry the connection.