Apache Netty SslHandler Packet Validation Vulnerability Leading to Denial-of-Service

A denial-of-service vulnerability has been identified in Apache Netty, specifically in the SslHandler component, within versions 4.1.91.Final through 4.1.117.Final. The issue arises because SslHandler fails to properly validate certain crafted packets, particularly when using the native SSLEngine, which can result in a native crash.

Impact

Exploitation of this vulnerability can cause a native crash, leading to a denial-of-service condition.

Reproduction

The vulnerability can be reproduced by sending specially crafted packets to a server using an affected version of Netty with the native SSLEngine enabled. This can be done over the network, targeting applications that rely on Netty for handling SSL/TLS communications.

Remediation

Users can upgrade to Netty version 4.1.118.Final or later, where the vulnerability has been patched. If an immediate upgrade is not possible, the native SSLEngine can be disabled or the code can be modified to use a manually created SSLEngine instance, applying the necessary mitigation.