CVE-2007-4924 in OpenH323
Summary
by MITRE
The Open Phone Abstraction Library (opal), as used by (1) Ekiga before 2.0.10 and (2) OpenH323 before 2.2.4, allows remote attackers to cause a denial of service (crash) via an invalid Content-Length header field in Session Initiation Protocol (SIP) packets, which causes a \0 byte to be written to an "attacker-controlled address."
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Analysis
by VulDB Data Team • 06/04/2025
The vulnerability described in CVE-2007-4924 represents a critical buffer overflow condition within the Open Phone Abstraction Library (opal) that affects several VoIP applications including Ekiga and OpenH323. This flaw manifests specifically when processing Session Initiation Protocol (SIP) packets containing malformed Content-Length header fields, creating a scenario where arbitrary memory corruption can occur. The vulnerability stems from insufficient input validation mechanisms within the library's SIP message parsing routines, which fail to properly sanitize or validate the Content-Length field values before processing them in memory operations.
The technical exploitation of this vulnerability occurs through manipulation of the SIP protocol's Content-Length header field, where an attacker crafts a malicious SIP packet containing an invalid Content-Length value that exceeds expected boundaries. When the affected opal library processes this malformed header, it attempts to write data to a memory address controlled by the attacker, resulting in a buffer overflow condition that ultimately leads to application crash or potential remote code execution. This type of vulnerability falls under the CWE-121 category of stack-based buffer overflow, though the specific implementation details suggest a more complex memory corruption scenario that could potentially be leveraged for privilege escalation or system compromise.
The operational impact of this vulnerability extends beyond simple denial of service, as it represents a fundamental security weakness in the core communication libraries used by VoIP applications. Organizations relying on Ekiga versions prior to 2.0.10 or OpenH323 versions before 2.2.4 face significant risk of service disruption and potential unauthorized access to their communication infrastructure. The vulnerability is particularly concerning in enterprise environments where VoIP systems serve as critical communication channels, as it could be exploited by attackers to disrupt business operations or gain unauthorized access to sensitive communication data. Attackers could potentially leverage this weakness to cause persistent service outages, making it an attractive target for both opportunistic and targeted attacks.
Mitigation strategies for this vulnerability require immediate patching of affected systems, with the primary solution being the upgrade to opal versions that include proper input validation and memory boundary checking mechanisms. System administrators should also implement network-based protections such as SIP protocol filtering and content validation at network boundaries to prevent malformed packets from reaching vulnerable applications. The implementation of proper input sanitization and boundary checking aligns with the ATT&CK framework's mitigation recommendations for preventing buffer overflow attacks, specifically targeting the execution of malicious code through memory corruption vulnerabilities. Additional defensive measures include network segmentation to isolate VoIP infrastructure, implementation of intrusion detection systems capable of identifying suspicious SIP traffic patterns, and regular security assessments of communication infrastructure to identify similar vulnerabilities in related components. Organizations should also consider implementing automated patch management systems to ensure timely deployment of security updates across all affected systems.