file-type detects the file type of a file, stream, or data. Prior to 21.3.1, a denial of service vulnerability exists in the ASF (WMV/WMA) file type detection parser. When parsing a crafted input where an ASF sub-header has a size field of zero, the parser enters an infinite loop. The payload value becomes negative (-24), causing tokenizer.ignore(payload) to move the read position backwards, so the same sub-header is read repeatedly forever. Any application that uses file-type to detect the type of untrusted/attacker-controlled input is affected. An attacker can stall the Node.js event loop with a 55-byte payload. Fixed in version 21.3.1.

Affected: npm: file-type

### Impact A denial of service vulnerability exists in the ASF (WMV/WMA) file type detection parser. When parsing a crafted input where an ASF sub-header has a `size` field of zero, the parser enters an infinite loop. The `payload` value becomes negative (-24), causing `tokenizer.ignore(payload)` to move the read position backwards, so the same sub-header is read repeatedly forever.

Any application that uses `file-type` to detect the type of untrusted/attacker-controlled input is affected. An attacker can stall the Node.js event loop with a 55-byte payload.

### Patches Fixed in version 21.3.1. Users should upgrade to >= 21.3.1.

### Workarounds Validate or limit the size of input buffers before passing them to `file-type`, or run file type detection in a worker thread with a timeout.

### References - Fix commit: 319abf871b50ba2fa221b4a7050059f1ae096f4f

### Reporter

crnkovic@lokvica.com

Ein entfernter, anonymer Angreifer kann eine Schwachstelle in IBM App Connect Enterprise ausnutzen, um einen Denial of Service Angriff durchzuführen.