CVE-2009-3704 in ZoIPer
Summary
by MITRE
ZoIPer 2.22, and possibly other versions before 2.24 Library 5324, allows remote attackers to cause a denial of service (crash) via a SIP INVITE request with an empty Call-Info header.
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Analysis
by VulDB Data Team • 01/01/2025
The vulnerability identified as CVE-2009-3704 affects ZoIPer 2.22 and potentially earlier versions up to Library 5324, representing a critical denial of service weakness in SIP-based VoIP applications. This flaw specifically targets the handling of SIP INVITE requests within the ZoIPer client software, where the application fails to properly validate or process incoming SIP messages containing empty Call-Info headers. The issue manifests as a remote crash condition that can be triggered by sending a specially crafted SIP INVITE message, making it particularly dangerous in networked environments where unauthorized parties might exploit this vulnerability to disrupt VoIP communications.
The technical implementation of this vulnerability stems from inadequate input validation within the SIP message processing pipeline of ZoIPer. When the application receives a SIP INVITE request with an empty Call-Info header, the software attempts to parse or process this malformed element without proper boundary checks or error handling mechanisms. This processing failure results in an unhandled exception or memory corruption that ultimately causes the application to terminate unexpectedly, leading to a denial of service condition for legitimate users attempting to establish VoIP connections. The vulnerability operates at the application layer of the network stack, specifically within the Session Initiation Protocol implementation that governs VoIP communication sessions.
From an operational perspective, this vulnerability presents significant risks to organizations relying on ZoIPer for voice communication services, particularly in enterprise environments where VoIP infrastructure is critical for business continuity. An attacker capable of sending SIP INVITE requests to targeted systems can effectively disrupt communication services by causing repeated crashes of the ZoIPer client applications. The remote nature of this attack means that malicious actors can exploit the vulnerability from outside the local network without requiring physical access or elevated privileges, making it an attractive target for attackers seeking to disrupt business operations or create service interruptions. The impact extends beyond simple service disruption as it can lead to cascading failures in VoIP networks where multiple clients or servers may be affected by the same attack vector.
The vulnerability aligns with CWE-129, which addresses improper validation of input boundaries, and represents a classic example of insufficient input validation in network protocol implementations. From an adversary perspective, this flaw maps to ATT&CK technique T1499.004, which involves network denial of service attacks targeting VoIP systems. Organizations should implement immediate mitigations including updating to ZoIPer version 2.24 or later, where the vulnerability has been addressed through proper input validation of SIP headers. Network-level protections such as SIP message filtering and rate limiting can provide additional defense in depth measures, while monitoring systems should be deployed to detect unusual SIP traffic patterns that might indicate exploitation attempts. Regular security assessments of VoIP infrastructure and proper patch management procedures are essential to prevent exploitation of similar vulnerabilities in other components of the communication ecosystem.