GHSA-66cw-h2mj-j39p: AVideo Affected by SSRF in BulkEmbed Thumbnail Fetch Allows Reading Internal Network Resources
SummaryThe BulkEmbed plugin's save endpoint (`plugin/BulkEmbed/save.json.php`) fetches user-supplied thumbnail URLs via `url_get_contents()` without SSRF protection. Unlike all six other URL-fetching endpoints in AVideo that were hardened with `isSSRFSafeURL()`, this code path was missed. An authenticated attacker can force the server to make HTTP requests to internal network resources and retrieve the responses by viewing the saved video thumbnail.DetailsWhen saving bulk-embedded videos, user-supplied thumbnail URLs from `$_POST['itemsToSave'][x]['thumbs']` flow directly into `url_get_contents()` with no SSRF validation:**`plugin/BulkEmbed/save.json.php:68-105`**The `url_get_contents()` function internally calls `isValidURLOrPath()` which only validates URL format (scheme, host presence) — it does **not** block requests to private IPs, localhost, or cloud metadata endpoints.**All other URL-fetching endpoints are protected.** The `isSSRFSafeURL()` function is called in:`plugin/Scheduler/Scheduler.php``plugin/LiveLinks/proxy.php` (two call sites)`plugin/AI/receiveAsync.json.php``objects/aVideoEncoder.json.php``objects/aVideoEncoderReceiveImage.json.php`BulkEmbed is the only URL-fetching endpoint that was not hardened.**This is a full-read SSRF**, not blind — the HTTP response body is written to disk as the video thumbnail and served to the attacker when they view the video poster image.PoC**Prerequisites:** Authenticated session with BulkEmbed permission. The `onlyAdminCanBulkEmbed` option defaults to `true` (line 41 of `BulkEmbed.php`), but is commonly disabled for multi-user platforms.**Step 1: Authenticate and obtain session cookie****Step 2: Send BulkEmbed save request with internal URL as thumbnail****Expected response:****Step 3: Retrieve the SSRF response from the saved thumbnail**The content of the internal HTTP response (e.g., AWS IAM role names from the metadata service) is returned as the image file content.**Cloud metadata example targets:**`http://169.254.169.254/latest/meta-data/iam/security-credentials/` — AWS IAM role names`http://169.254.169.254/latest/meta-data/iam/security-credentials/{role}` — temporary AWS credentials`http://metadata.google.internal/computeMetadata/v1/` — GCP metadata (requires header, may not work)`http://169.254.169.254/metadata/instance?api-version=2021-02-01` — Azure instance metadata**Internal network scanning:**`http://10.0.0.1:8080/` — probe internal services`http://localhost:3306/` — probe local database portsImpact**Cloud credential theft:** On AWS/GCP/Azure-hosted instances, an attacker can retrieve cloud IAM credentials from the metadata service, potentially gaining access to cloud infrastructure (S3 buckets, databases, other services).**Internal network reconnaissance:** Attacker can map internal network topology by probing private IP ranges and observing which requests return content vs. timeout.**Internal service data exfiltration:** Any HTTP-accessible internal service (admin panels, monitoring dashboards, databases with HTTP interfaces) can have its responses exfiltrated through the thumbnail mechanism.**Scope change:** The attack crosses security boundaries — from the web application into the internal network/cloud infrastructure, which is a different trust zone.Recommended FixAdd `isSSRFSafeURL()` validation before the `url_get_contents()` call in `plugin/BulkEmbed/save.json.php`, consistent with all other URL-fetching endpoints:
CVSS v3.1: 5