CVE-2023-42809 (Java, published 2023-10-04T20:15Z)
Description: value: Redisson is a Java Redis client that uses the Netty framework. Prior to version 3.22.0, some of the messages received from the Redis server contain Java objects that the client deserializes without further validation. Attackers that manage to trick clients into communicating with a malicious server can include especially crafted objects in its responses that, once deserialized by the client, force it to execute arbitrary code. This can be abused to take control of the machine the client is running in. Version 3.22.0 contains a patch for this issue.

Some post-fix advice is available. Do NOT use `Kryo5Codec` as deserialization codec, as it is still vulnerable to arbitrary object deserialization due to the `setRegistrationRequired(false)` call. On the contrary, `KryoCodec` is safe to use. The fix applied to `SerializationCodec` only consists of adding an optional allowlist of class names, even though making this behavior the default is recommended. When instantiating `SerializationCodec` please use the `SerializationCodec(ClassLoader classLoader, Set<String> allowedClasses)` constructor to restrict the allowed classes for deserialization.
Severity: nan (CVSS v3 base score: 8.8)
Weakness: CWE-502 \u2014 Deserialization of Untrusted Data
The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid.
Repository: https://github.com/redisson/redisson
Files changed:
redisson/src/main/java/org/redisson/codec/CustomObjectInputStream.java
redisson/src/main/java/org/redisson/codec/SerializationCodec.java
Commit message: Feature - allowedClasses setting added to SerializationCodec https://github.com/redisson/redisson/security/code-scanning/4


Vulnerable code:
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectStreamClass;
    
        return Proxy.getProxyClass(classLoader, loadedClasses.toArray(new Class[loadedClasses.size()]));
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufAllocator;
import io.netty.buffer.ByteBufInputStream;
import io.netty.buffer.ByteBufOutputStream;
                        inputStream = new CustomObjectInputStream(classLoader, in);
    

Fixed code:
import java.io.*;
import java.util.Set;
    private Set<String> allowedClasses;

    public CustomObjectInputStream(ClassLoader classLoader, InputStream in,Set<String> allowedClasses) throws IOException {
        super(in);
        this.classLoader = classLoader;
        this.allowedClasses = allowedClasses;
    }

            if (allowedClasses != null && !allowedClasses.contains(name)) {
                throw new InvalidClassException("Class " + name + " isn't allowed");
            }
        return Proxy.getProxyClass(classLoader, loadedClasses.toArray(new Class[0]));
import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufAllocator;
import io.netty.buffer.ByteBufInputStream;
import io.netty.buffer.ByteBufOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.Set;
                        inputStream = new CustomObjectInputStream(classLoader, in, allowedClasses);

    private Set<String> allowedClasses;
        this.allowedClasses = codec.allowedClasses;
    }

    public SerializationCodec(ClassLoader classLoader, Set<String> allowedClasses) {
        this.classLoader = classLoader;
        this.allowedClasses = allowedClasses;