Affected versions fo this package are vulnerable to Denial of Service (DoS) attacks.
windowBits parameter controls how much of a message zlib keeps in memory while compressing it. A larger "window", as it's called, means more opportunities to spot and compress repeated bits of text, but results in higher memory usage.
windowBits is the base-2 logarithm of the size of this window in bytes, and previously could take any integer value from 8 to 15.
This problem (Node.js crashing or throwing an exception) could be remotely exploited using some of the existing WebSocket clients that may request a value of 8 for
windowBits in certain cases or with a custom built WebSocket client. There may also exist other vectors through which a
zLib operation would be initiated by a remote request with a window size that results in a value of
windowBits of 8.
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
node to versions 4.8.5, 6.11.5, 8.8.0 or higher.