Denial of Service (DoS) Affecting com.squareup.okhttp3:okhttp-brotli package, versions [0,]

Affected versions of this package are vulnerable to Denial of Service (DoS) when using a BrotliInterceptor and surfing to a malicious web server, or when an attacker can perform MitM to inject a Brotli zip-bomb into an HTTP response. The code does not guard against decompression bombs, which can crash the process due to memory exhaustion. With Brotli, a file of several KBs can be decompressed into 10GB.

Users who are unable to upgrade to the fixed version should remove any usage of the BrotliInterceptor class.

import okhttp3.Call;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;
import okhttp3.brotli.BrotliInterceptor;
import java.io.IOException;
public class JavassistIntTruncationExample
{
public static void main(String argv[]) throws IOException {
    OkHttpClient client = new OkHttpClient.Builder()
            .addInterceptor(BrotliInterceptor.INSTANCE)
            .build();
    Request request = new Request.Builder()
            .url("http://127.0.0.1:8080")
            .build();
    Call call = client.newCall(request);
    Response response = call.execute();
    System.out.println(response.body().bytes().length);
}
}

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

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