The proxy-check-i PyPI package (versions 0.1.0 and 0.1.1) includes a bundled Go binary acting as a reverse-SSH daemon. This daemon is launched via the package's entry point 'proxy-check-i' which calls the binary using os.execv. The daemon creates a device lock file and repeatedly connects outbound to a relay server using the 'overthing' tunnel library, enabling remote shell access, command execution, pty allocation, and TCP port forwarding. SSH authentication is restricted to a single hardcoded ed25519 public key embedded at build time, allowing only the key holder to connect. This reverse connection design circumvents inbound firewall rules. The PyPI metadata omits any mention of the SSH server or relay behavior, preventing users from recognizing the malicious functionality. Consequently, hosts running this package are exposed to remote control by the attacker.

Hosts that install and run proxy-check-i versions 0.1.0 or 0.1.1 are exposed to full remote control by an attacker possessing the embedded SSH private key. The attacker can gain persistent shell access, execute arbitrary commands, allocate pseudo-terminals, and forward TCP ports, effectively compromising the confidentiality, integrity, and availability of the affected system. The reverse-SSH design bypasses inbound firewall protections, increasing the risk of undetected remote compromise.

No official patch or remediation is currently available for proxy-check-i. Users should immediately uninstall versions 0.1.0 and 0.1.1 of this package and avoid running the 'proxy-check-i' command. Since the malicious behavior is embedded in the package itself, removing the package and any associated binaries is necessary to eliminate the threat. Monitor for any unauthorized SSH connections using the embedded key and investigate any systems where this package was installed. Patch status is not yet confirmed — check the vendor or PyPI advisories for updates.