PraisonAI vulnerable to Server-Side Request Forgery via DNS rebinding bypass in webhook_url validation

Summary

The webhook_url field in the Jobs API silently passes validation when DNS resolution fails (socket.gaierror), enabling DNS rebinding attacks. An attacker's domain can initially resolve to a public IP (passing validation) then switch to an internal IP before the server makes the HTTP request.

Details

The validator catches socket.gaierror and silently allows the URL:

# src/praisonai/praisonai/jobs/models.py:55
try:
    ip = socket.gethostbyname(hostname)
    ip_obj = ipaddress.ip_address(ip)
    if ip_obj.is_private or ip_obj.is_loopback:
        raise ValueError("private address")
except socket.gaierror:
    pass  # BUG: DNS failure silently ignored → SSRF bypass

The HTTP call is made later with no re-validation:

# src/praisonai/praisonai/jobs/executor.py:402
async with httpx.AsyncClient() as client:
    await client.post(job.webhook_url, ...)  # no second IP check

Proof of Concept

DNS rebinding flow:

1. Register attacker.com with TTL=1s → resolves to 1.2.3.4 (public IP)
2. Submit job: webhook_url=http://attacker.com/callback
3. Validation passes (public IP)
4. Switch DNS: attacker.com → 127.0.0.1
5. Job completes → server POSTs to 127.0.0.1 → internal SSRF

Unresolvable domain bypass (no DNS rebinding required):

curl -X POST http://:8005/api/v1/runs \
  -d '{"prompt":"run","webhook_url":"http://unresolvable.internal/cb","agent_yaml":"..."}'
# Validation: gaierror → pass → URL accepted

Impact

SSRF to internal HTTP services: admin panels, databases, and cloud metadata APIs (e.g., http://169.254.169.254/). Exploitable without authentication.