npm PraisonAI SandboxExecutor network-isolated mode does not block non-proxy-aware network clients
Summary
The published npm package praisonai exports a TypeScript SandboxExecutor with a network-isolated mode. The CLI lists that mode as:
```text
network-isolated No network access (proxy blocked)
```
The implementation does not create a network namespace, firewall rule, socket filter, or proxy-enforced execution boundary. It only injects proxy environment variables into the child process:
```ts
http_proxy: 'http://localhost:0',
https_proxy: 'http://localhost:0',
HTTP_PROXY: 'http://localhost:0',
HTTPS_PROXY: 'http://localhost:0',
no_proxy: '',
NO_PROXY: ''
```
Clients that do not explicitly honor those proxy variables continue to use the host network stack. A local-only PoV shows that, inside mode: "network-isolated", a proxy-aware Node invocation is stopped, while a plain Node HTTP client reaches a loopback HTTP server from the same sandboxed command environment.
This is a network-isolation protection failure in an exported npm API and CLI mode. It is not a generic claim that every PraisonAI sandbox backend is affected.
Technical Details
src/praisonai-ts/src/cli/features/sandbox-executor.ts declares the mode:
```ts
export type SandboxMode = 'disabled' | 'basic' | 'strict' | 'network-isolated';
```
SandboxExecutor.spawn() starts the command through the host shell and passes only the environment returned by buildEnv():
```ts
const proc = spawn('sh', ['-c', command], {
cwd: this.config.cwd,
env,
timeout: this.config.timeout,
stdio: ['pipe', 'pipe', 'pipe']
});
```
For network-isolated, buildEnv() does not apply an OS-level network restriction. It only sets proxy variables:
```ts
case 'network-isolated':
// No network access (requires additional OS-level setup)
return {
...baseEnv,
http_proxy: 'http://localhost:0',
https_proxy: 'http://localhost:0',
HTTP_PROXY: 'http://localhost:0',
HTTPS_PROXY: 'http://localhost:0',
no_proxy: '',
NO_PROXY: ''
};
```
The CLI mode listing presents this as no network access:
```ts
'network-isolated': 'No network access (proxy blocked)'
```
That creates a false boundary. Proxy variables affect only clients that choose to read and honor them. Other clients can still open sockets directly from the child process.
Why This Is Not Intended Behavior
The vulnerable behavior is not "commands can run." The issue is that a mode named network-isolated and displayed to users as "No network access" still allows direct socket access.
The source comment says network-isolated requires additional OS-level setup, which is consistent with the finding: proxy variables alone are not a network isolation mechanism. The exported npm API and CLI mode do not provide such setup or warn callers that this mode is only a best-effort proxy hint.
If the intended behavior is merely "set proxy variables for cooperative clients," the mode name and CLI description should be changed so users do not rely on it as a security boundary.
PoV
Run from a local reproduction checkout:
```bash
node poc/pov_poc.js 1.7.1
```
The PoV:
1. Installs npm:[email protected] into a temporary project.
2. Starts a harmless HTTP server bound to 127.0.0.1 on a random local port.
3. Creates new SandboxExecutor({ mode: "network-isolated" }).
4. Confirms the child environment contains the proxy variables.
5. Runs node --use-env-proxy client.js as a proxy-aware control. It fails and does not reach the server.
6. Runs node client.js without proxy opt-in. It reaches the server and prints the marker.
Observed output summary from evidence/pov-npm-1.7.1.json:
```json
{
"version": "1.7.1",
"mode": "network-isolated",
"control": {
"localServerBoundToLoopback": true,
"proxyVariablesSet": true,
"proxyAwareClientStopped": true,
"requestReachedLoopbackServer": true
},
"observed": {
"proxyAwareRun": {
"success": false,
"stdout": "",
"exitCode": 2
},
"netRun": {
"success": true,
"stdout": "BODY=poc\n",
"exitCode": 0
},
"loopbackHitCount": 1
},
"vulnerable": true
}
```
The PoV is local-only. It does not contact any external host after npm package installation, and it does not use cloud metadata or destructive commands.
PoC
The PoV section above contains the local reproduction command, input, and decisive output.
Impact
Applications often use sandbox network controls to prevent prompt-injected, user-supplied, or model-generated commands from exfiltrating secrets or reaching internal services. A caller who relies on network-isolated mode for that boundary can still get network egress by using any client that ignores proxy environment variables or by using direct socket APIs.
Depending on the hosting environment, this can allow:
- exfiltration from commands that can read local files, process output, or inherited environment variables;
- access to l
