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Security policy

Important boundary

This project starts Codex Desktop with Chromium remote debugging and a temporary Electron main-process Inspector on random 127.0.0.1 ports. Any untrusted process already running as your Windows user may be able to use the renderer endpoint to execute renderer code or use the Inspector during its startup window to execute main-process Node code. Run the workaround only on a trusted personal machine.

The launcher requires the Electron main-process Inspector to become unreachable after setup. If that verification fails, it stops the special instance and restarts Codex normally. The renderer endpoint remains available until Codex exits because Chromium does not provide a supported runtime switch to remove it.

Persistent supervisor boundaries

The persistent tray supervisor is installed per current user, not per machine:

  • The scheduled task Codex Control Other Devices Supervisor runs unelevated with InteractiveToken, RunLevel=Limited, and MultipleInstances=IgnoreNew. It cannot grant administrator rights and is never registered as a service or IFEO entry.
  • The supervisor writes only under %LOCALAPPDATA%\CodexControlOtherDevices; the install root, state, runtime, and logs are part of the current user's trust root. A same-user process that can already modify your user files is inside the threat model.
  • Manifest, active-pointer, and state hashes detect corruption and tampering, but they do not authenticate the author of a checkout. Source trust comes from user review of the repository before install.
  • The renderer CDP endpoint remains on 127.0.0.1 for the whole special session and is available to same-user processes. The main-process Inspector is limited to the startup window and must close with an explicit ECONNREFUSED check.
  • Lifecycle work is fenced by the active runtime generation and lease epoch. The supervisor also binds safe-exit and recovery records to a trusted token AuthenticationId (LUID), SID, and Windows session ID; PID or thread identity alone is never enough to authorize a lifecycle action.
  • The tray exposes only status, one repair action, language, logs, About, and safe Exit. Exit writes a protected intent for the current logon and may restore Codex to ordinary mode before protection stops.
  • The tray has no uninstall command. The portable release uses the installed Uninstall-CodexControlOtherDevices.ps1 entry. It invokes the same external, fail-closed bootstrap, which verifies the runtime manifest, generation, epoch, SID, and session. Only after that proof does a staged finalizer remove the marker-bound portable payload. A failed proof leaves both application files and the installer payload in place.
  • The ZIP release is bound by the release manifest, payload manifest, and SHA-256. Its entrypoint validates every extracted payload file and runs a Defender custom scan before copying files to the current-user installer root. It does not disable Defender or add exclusions.

Device-key storage

  • The private P-256 key is encrypted with Windows DPAPI using CurrentUser scope before it is written to disk.
  • The encrypted store is located at %CODEX_HOME%\remote-control-device-keys.windows.json; if CODEX_HOME is unset, the default is %USERPROFILE%\.codex\remote-control-device-keys.windows.json.
  • Decryption occurs when Codex calls signDeviceKey() and when a create/delete operation validates or migrates every existing record before replacing the store. Public-key reads do not normally need the private material.
  • The compatibility value sent to Codex is os_protected_nonextractable, but this JavaScript fallback is not equivalent to a hardware-backed TPM key.
  • The external uninstall flow leaves the encrypted store in place. It has no key backup, export, or removal switch, and it does not alter server-side authorization. Revoke the device in Codex first when revocation is intended.

Safer operating practice

  1. Complete the MFA, SSO, or passkey required by the account/workspace. The account used for this project's test required MFA before enrollment.
  2. Keep Windows and Codex Desktop updated.
  3. Run Test-CodexControlOtherDevices.ps1 after every Codex update.
  4. Treat its text-sentinel result as a heuristic, not proof of compatibility; audit new builds before updating the supported technique.
  5. Launch Codex normally whenever remote desktop-to-desktop control is not needed.
  6. Revoke the controller device in Codex before removing its local key store.
  7. Do not run the supervisor on a shared or untrusted machine; the tray session keeps the renderer debugging endpoint open on 127.0.0.1.
  8. Review %LOCALAPPDATA%\CodexControlOtherDevices\logs\ before sharing any diagnostic log; entries contain local paths but must never contain tokens, device keys, or account credentials.

Reporting a vulnerability

Please use GitHub's Security → Report a vulnerability flow after Private Vulnerability Reporting is enabled for this repository. If the private form is not visible, open a public issue containing only a request for a private contact channel—do not include technical exploit details. Never include ChatGPT session data, account tokens, device keys, or diagnostic logs containing private paths in a public issue.