Yes. Exploitation of some very secure (and offline) networks have been accomplished via USB.

"noexec" and other features are not always enough to prevent keyloggers and other malicious devices from operating.

A reasonably good solution is to block all USB devices except those in a small whitelist of VIDs/SIDs (i.e. Vendor IDs and Serial Numbers). This gives you good security, as long as you guard who has access to the list of trusted VIDs and SIDs.