Impact
An attacker that has access to nodes within the cluster may be able to SFTP to the Proxy Service. The user's permissions on the Proxy server are still respected, so files can only be read or modified on the Proxy if the user has system access to read or write to them.
Patches
Fixed in versions 14.2.4, 13.4.13 and 12.4.31.
Workarounds
This issue can be mitigated by ensuring that regular users do not have a valid principal on the proxy server. To be exploitable, the user's login must exist on a proxy server and the Teleport binary must have permissions to start a session with this user.
References
Tener Reporter
Impact
An attacker that has access to nodes within the cluster may be able to SFTP to the Proxy Service. The user's permissions on the Proxy server are still respected, so files can only be read or modified on the Proxy if the user has system access to read or write to them.
Patches
Fixed in versions 14.2.4, 13.4.13 and 12.4.31.
Workarounds
This issue can be mitigated by ensuring that regular users do not have a valid principal on the proxy server. To be exploitable, the user's login must exist on a proxy server and the Teleport binary must have permissions to start a session with this user.
References