CVE-2023-46239 in quic-go
Summary
by MITRE • 10/31/2023
quic-go is an implementation of the QUIC protocol in Go. Starting in version 0.37.0 and prior to version 0.37.3, by serializing an ACK frame after the CRYTPO that allows a node to complete the handshake, a remote node could trigger a nil pointer dereference (leading to a panic) when the node attempted to drop the Handshake packet number space. An attacker can bring down a quic-go node with very minimal effort. Completing the QUIC handshake only requires sending and receiving a few packets. Version 0.37.3 contains a patch. Versions before 0.37.0 are not affected.
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Analysis
by VulDB Data Team • 11/22/2023
The vulnerability CVE-2023-46239 affects the quic-go library, a Go implementation of the QUIC protocol that is widely used for secure network communications. This issue represents a critical denial of service vulnerability that can be exploited remotely with minimal effort to crash QUIC-enabled applications. The vulnerability specifically impacts versions 0.37.0 through 0.37.2 of the quic-go library, where a flaw in the handshake processing logic creates a condition that leads to a nil pointer dereference during packet handling. The affected code path occurs when a remote attacker successfully completes the QUIC handshake process by sending properly crafted packets that include an ACK frame followed by CRYPTO frames, which triggers an unexpected state transition in the protocol implementation.
The technical flaw stems from improper handling of packet number spaces during the handshake completion phase, particularly when the system attempts to drop the Handshake packet number space after a successful handshake. This condition manifests as a nil pointer dereference error that results in a panic and subsequent process termination. The vulnerability is classified as a CWE-476 Null Pointer Dereference, which occurs when code attempts to access a memory location through a pointer that has not been properly initialized or has been set to null. The attack vector requires only a minimal number of packets to complete the handshake process, making it extremely easy to exploit and allowing an attacker to bring down any quic-go node without significant resources or advanced technical knowledge.
From an operational perspective, this vulnerability poses a severe risk to systems relying on quic-go for network communications, particularly those serving as QUIC servers or applications that accept incoming QUIC connections. The impact extends beyond simple service disruption as the panic condition can affect the entire application process, potentially leading to cascading failures in distributed systems where QUIC is used for inter-service communication. The low exploit complexity and high impact make this vulnerability particularly dangerous in production environments where availability is critical. Network infrastructure components, web servers, and any application using quic-go as a dependency could become immediately vulnerable to this attack, with the potential for widespread disruption across multiple services simultaneously.
The recommended mitigation strategy involves upgrading to quic-go version 0.37.3 or later, which contains the necessary patch to address the nil pointer dereference condition. Organizations should prioritize this update across all systems utilizing the affected library, particularly those running QUIC servers or applications that handle incoming connections. Additionally, implementing network-level protections such as rate limiting and connection monitoring can provide additional defense in depth. The vulnerability demonstrates the importance of proper state management in cryptographic protocol implementations and highlights the need for thorough testing of edge cases during handshake completion. Security teams should also consider monitoring for unusual connection patterns or rapid connection termination that might indicate exploitation attempts, as the panic condition may leave detectable traces in system logs or monitoring systems.