CVE-2004-0120 in Windows
Summary
by MITRE
The Microsoft Secure Sockets Layer (SSL) library, as used in Windows 2000, Windows XP, and Windows Server 2003, allows remote attackers to cause a denial of service via malformed SSL messages.
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Analysis
by VulDB Data Team • 01/02/2025
The vulnerability identified as CVE-2004-0120 represents a critical flaw in Microsoft's implementation of the Secure Sockets Layer protocol across multiple operating systems including Windows 2000, Windows XP, and Windows Server 2003. This weakness specifically targets the SSL library that handles encrypted communications between clients and servers, creating a potential pathway for malicious actors to disrupt normal service operations. The vulnerability stems from inadequate input validation within the SSL processing routines, which fail to properly handle malformed or crafted SSL protocol messages that deviate from standard protocol specifications. Such malformed messages can be constructed to exploit the library's parsing mechanisms, leading to unexpected behavior and system instability.
The technical implementation of this vulnerability lies in how the SSL library processes incoming protocol data structures without sufficient validation checks. When the library encounters malformed SSL messages, particularly those containing invalid length fields, unexpected packet sequences, or corrupted data structures, the parsing logic fails to gracefully handle these anomalies. This failure results in memory corruption or execution flow disruption within the SSL processing components, ultimately causing the affected system to crash or become unresponsive. The flaw operates at the protocol layer where SSL handshake negotiations occur, making it particularly dangerous as it can be triggered during normal secure communication establishment processes. According to CWE classification, this vulnerability maps to CWE-129: Improper Validation of Array Index, as the SSL library fails to validate the bounds of data structures before processing them, and CWE-248: Uncaught Exception, since the library does not properly handle exceptional conditions during SSL message processing.
The operational impact of CVE-2004-0120 extends beyond simple service disruption to potentially enable more sophisticated attack vectors. Remote attackers can leverage this vulnerability to perform denial of service attacks against targeted systems, causing widespread availability issues for critical services such as web servers, email servers, and other SSL-enabled applications. The vulnerability's remote exploitability means that attackers do not require physical access or local privileges to trigger the condition, making it particularly dangerous in networked environments where systems are exposed to untrusted traffic. Organizations running affected versions of Windows systems face significant risk of service interruption, especially during peak usage periods when SSL connections are most frequent. The attack surface is broad as any service utilizing the affected SSL library can be targeted, including web applications, database servers, and enterprise applications that rely on secure communications.
From a threat modeling perspective, this vulnerability aligns with ATT&CK technique T1499.004: Endpoint Denial of Service, specifically targeting the availability aspect of the CIA triad. The vulnerability can be exploited by attackers using automated scanning tools to identify vulnerable systems and then deliver malicious SSL messages to trigger the denial of service condition. Network defenders should note that this vulnerability was particularly concerning in enterprise environments where SSL was widely used for securing business-critical communications, as successful exploitation could result in significant operational disruption and potential financial losses. Mitigation strategies should include immediate deployment of Microsoft security patches, network segmentation to limit exposure, and implementing monitoring solutions to detect unusual SSL traffic patterns that might indicate exploitation attempts. Additionally, organizations should consider implementing intrusion detection systems that can identify malformed SSL traffic signatures associated with this specific vulnerability, as the attack pattern is relatively consistent and detectable through network traffic analysis.