Denial of Service (DoS) Affecting multer package, versions >=2.2.0 <2.4.0

Affected versions of this package are vulnerable to Denial of Service (DoS) via incomplete cleanup of uploaded files when a request is aborted before the storage engine assigns a file path. When an upload is aborted mid-flight, the finishAbort function in make-middleware.js snapshots only the files that already have a path at the moment of abort; any file whose storage engine completes naming and writing after that snapshot is never added to the removal list and is never deleted, leaving orphaned files on disk (or in the configured storage backend). An attacker can repeatedly send and abort multipart upload requests to accumulate unbounded orphaned files, exhausting available disk space.

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.

Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.

One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.

When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.

Two common types of DoS vulnerabilities:

• High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.

• Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm ws package

• GitHub Commit v2.4.0
• Maintainer's Advisory