CVE-2014-3488 in Netty
Summary
by MITRE
The SslHandler in Netty before 3.9.2 allows remote attackers to cause a denial of service (infinite loop and CPU consumption) via a crafted SSLv2Hello message.
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Analysis
by VulDB Data Team • 01/11/2026
The vulnerability identified as CVE-2014-3488 resides within the SslHandler component of the Netty networking framework, specifically affecting versions prior to 3.9.2. This flaw represents a critical security issue that enables remote attackers to execute a denial of service attack by exploiting a weakness in the SSL/TLS handshake process. The vulnerability manifests when the system receives a specially crafted SSLv2Hello message, which is a legacy handshake protocol message that should be rejected by modern SSL implementations. The flaw demonstrates a classic example of inadequate input validation and error handling within cryptographic protocol implementations.
The technical root cause of this vulnerability lies in how the SslHandler processes SSLv2Hello messages, which are designed to be incompatible with modern SSL/TLS versions. When a malformed SSLv2Hello message is received, the handler enters an infinite loop during the processing phase, consuming excessive CPU resources and effectively rendering the affected system unavailable to legitimate users. This behavior stems from insufficient boundary checks and state management within the SSL handshake logic, causing the system to continuously iterate through processing steps without proper termination conditions. The vulnerability maps to CWE-835, which describes the weakness of an infinite loop or infinite recursion, and represents a specific case of improper input validation in cryptographic libraries.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be exploited by attackers to launch resource exhaustion attacks against network services. Attackers can repeatedly send crafted SSLv2Hello messages to consume system resources, potentially leading to complete system unavailability or cascading failures in network infrastructure. This vulnerability affects any application using Netty versions prior to 3.9.2 that handles SSL connections, making it particularly dangerous in high-traffic environments where resource exhaustion can quickly lead to widespread service degradation. The attack vector requires only network access to the vulnerable service, making it easily exploitable from remote locations without requiring authentication or specialized privileges.
Organizations affected by this vulnerability should immediately upgrade to Netty version 3.9.2 or later, which includes proper handling of SSLv2Hello messages and prevents the infinite loop condition. Additional mitigations include implementing network-level filtering to block SSLv2Hello messages at the firewall or load balancer level, configuring rate limiting to restrict the number of SSL handshake attempts, and monitoring system resources for unusual CPU consumption patterns. Security teams should also consider implementing intrusion detection systems that can identify and alert on suspicious SSL handshake patterns. From an ATT&CK framework perspective, this vulnerability maps to techniques involving resource exhaustion and denial of service, specifically targeting the availability aspect of the CIA triad. The vulnerability demonstrates the importance of proper input validation in cryptographic libraries and highlights the need for robust error handling in security-critical components that process network protocols.