🛡️ GHSA-fm76-w8jw-xf8m — plugins-loader

@saltcorn/plugins-loader unsanitized plugin name leads to a remote code execution (RCE) vulnerability when creating plugins using git source

Summary

When creating a new plugin using the git source, the user-controlled value req.body.name is used to build the plugin directory where the location will be cloned. The API used to execute the git clone command with the user-controlled data is child_process.execSync. Since the user-controlled data is not validated, a user with admin permission can add escaping characters and execute arbitrary commands, leading to a command injection vulnerability.

Details

Relevant code from source (req.body) to sink (child_process.execSync).

• file: https://github.com/saltcorn/saltcorn/blob/v1.0.0-beta.13/packages/server/routes/plugins.js#L1400

```js

router.post(

"/",

isAdmin,

error_catcher(async (req, res) => {

const plugin = new Plugin(req.body); // [1]

[...]

try {

await load_plugins.loadAndSaveNewPlugin( // [3]

plugin,

schema === db.connectObj.default_schema || plugin.source === "github"

);

[...]

}

})

);

```

• file: https://github.com/saltcorn/saltcorn/blob/v1.0.0-beta.13/packages/saltcorn-data/models/plugin.ts#L44

```js

class Plugin {

[...]

constructor(o: PluginCfg | PluginPack | Plugin) {

[...]

this.name = o.name; // [2]

[...]

}

```

• file: https://github.com/saltcorn/saltcorn/blob/v1.0.0-beta.13/packages/server/load_plugins.js#L64-L65

```js

const loadAndSaveNewPlugin = async (plugin, force, noSignalOrDB) => {

[...]

const loader = new PluginInstaller(plugin); // [4]

const res = await loader.install(force); // [7]

[...]

};

```

• file: https://github.com/saltcorn/saltcorn/blob/v1.0.0-beta.13/packages/plugins-loader/plugin_installer.js#L41-L61

```js

class PluginInstaller {

constructor(plugin, opts = {}) {

[...]

const tokens =

plugin.source === "npm"

? plugin.location.split("/")

: plugin.name.split("/"); // [5]

[...]

this.tempDir = join(this.tempRootFolder, "temp_install", ...tokens); // [6]

[...]

}

async install(force) {

[...]

if (await this.prepPluginsFolder(force, pckJSON)) { // [8]

[...]

}

async prepPluginsFolder(force, pckJSON) {

[...]

switch (this.plugin.source) {

[...]

case "git":

if (force || !(await pathExists(this.pluginDir))) {

await gitPullOrClone(this.plugin, this.tempDir); // [9]

[...]

}

```

• file: https://github.com/saltcorn/saltcorn/blob/v1.0.0-beta.13/packages/plugins-loader/download_utils.js#L112

```js

const gitPullOrClone = async (plugin, pluginDir) => {

[...]

if (fs.existsSync(pluginDir)) {

execSync(git ${setKey} -C ${pluginDir} pull);

} else {

execSync(git ${setKey} clone ${plugin.location} ${pluginDir}); // [10]

}

[...]

};

```

PoC

• check that the file will be created by the command echo "hello">/tmp/HACKED does not exists:

```

cat /tmp/HACKED

cat: /tmp/HACKED: No such file or directory

```

• login with an admin account
• visit http://localhost:3000/plugins/new
• enter the following fields:
• Name: ;echo "hello">/tmp/HACKED
• Source: git
• other fields blank
• click Create
• you will get an error saying ENOENT: no such file or directory, .... but the command touch /tmp/HACKED will be executed
• to verify:

```

cat /tmp/HACKED

hello

```

Impact

Remote code execution

Recommended Mitigation

Sanitize the pluginDir value before passing to execSync. Alternatively, use child_process. execFileSync API (docs: https://nodejs.org/api/child_process.html#child_processexecfilesyncfile-args-options)