SSHAgentWeiterleitung

SSHAgentWeiterleitung, often abbreviated as SSH agent forwarding, is a feature of the Secure Shell (SSH) protocol that allows a user to securely forward their local SSH authentication agent connection to a remote server. This means that an SSH key stored and managed by an agent on the user's local machine can be used to authenticate to other servers accessed *from* the remote server, without the private key ever leaving the local machine.

The process begins when a user connects to a remote server using SSH with agent forwarding enabled. The local SSH agent holds the user's private key(s) in memory. When the user then attempts to connect from the remote server to another server (e.g., to push code to a Git repository), the remote server forwards the authentication request back to the local SSH agent through the established SSH connection. The local agent then uses the appropriate private key to sign the authentication challenge, and the signature is sent back through the forwarding mechanism.

This is particularly useful for situations where a user needs to access multiple servers in a chain, or when performing actions like Git operations that require authentication to a separate server. The primary security benefit is that private keys are never copied or exposed on the intermediate remote server, significantly reducing the risk of compromise. However, enabling agent forwarding on a less trusted remote server can introduce risks, as a compromised attacker on that server could potentially use the forwarded agent connection to access other resources. Therefore, it's crucial to only enable agent forwarding when connecting to trusted remote systems.