Headline
GHSA-fm76-w8jw-xf8m: @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
 
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
 
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
 
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
 
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
 
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/HACKEDdoes 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
 
 - Name: 
 - click 
Create - you will get an error saying 
ENOENT: no such file or directory, ....but the commandtouch /tmp/HACKEDwill 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)
- GitHub Advisory Database
 - GitHub Reviewed
 - GHSA-fm76-w8jw-xf8m
 
@saltcorn/plugins-loader unsanitized plugin name leads to a remote code execution (RCE) vulnerability when creating plugins using git source
High severity GitHub Reviewed Published Oct 3, 2024 in saltcorn/saltcorn • Updated Oct 3, 2024
Package
npm @saltcorn/plugins-loader (npm)
Affected versions
<= 1.0.0-beta.13
Patched versions
1.0.0-beta.14
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
 
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
 
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
 
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
 
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
 
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)
References
- GHSA-fm76-w8jw-xf8m
 - saltcorn/saltcorn@024f19a
 - https://github.com/saltcorn/saltcorn/blob/v1.0.0-beta.13/packages/plugins-loader/download_utils.js#L112
 - https://github.com/saltcorn/saltcorn/blob/v1.0.0-beta.13/packages/plugins-loader/plugin_installer.js#L41-L61
 - https://github.com/saltcorn/saltcorn/blob/v1.0.0-beta.13/packages/saltcorn-data/models/plugin.ts#L44
 - https://github.com/saltcorn/saltcorn/blob/v1.0.0-beta.13/packages/server/load_plugins.js#L64-L65
 - https://github.com/saltcorn/saltcorn/blob/v1.0.0-beta.13/packages/server/routes/plugins.js#L1400
 
Published to the GitHub Advisory Database
Oct 3, 2024