CVE-2009-2496 in Office
Summary
by MITRE
Heap-based buffer overflow in the Office Web Components ActiveX Control in Microsoft Office XP SP3, Office 2003 SP3, Office XP Web Components SP3, Office 2003 Web Components SP3, Office 2003 Web Components SP1 for the 2007 Microsoft Office System, Internet Security and Acceleration (ISA) Server 2004 SP3 and 2006 SP1, and Office Small Business Accounting 2006 allows remote attackers to execute arbitrary code via unspecified parameters to unknown methods, aka "Office Web Components Heap Corruption Vulnerability."
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Analysis
by VulDB Data Team • 01/05/2025
The CVE-2009-2496 vulnerability represents a critical heap-based buffer overflow affecting Microsoft Office Web Components ActiveX controls across multiple software versions including Office XP SP3, Office 2003 SP3, and various ISA Server configurations. This vulnerability resides within the Office Web Components ActiveX control implementation and specifically targets heap memory management during parameter processing within unknown methods. The flaw enables remote attackers to achieve arbitrary code execution through manipulation of unspecified parameters, making it particularly dangerous for web-based attack scenarios where untrusted input can be processed by vulnerable components. The vulnerability is categorized under CWE-121 Heap-based Buffer Overflow, which is a well-documented weakness in software security that occurs when more data is written to a buffer located on the heap than the buffer can accommodate, leading to memory corruption and potential code execution.
The technical implementation of this vulnerability demonstrates how ActiveX controls in Microsoft Office systems can be exploited through improper input validation and memory handling. When the vulnerable ActiveX control processes specific parameters through unknown methods, it fails to properly validate buffer boundaries, allowing attackers to overflow heap memory structures. This type of vulnerability is particularly concerning because ActiveX controls are designed to run with elevated privileges in web browsers, making successful exploitation potentially devastating. The attack vector is remote, meaning that malicious actors can trigger the vulnerability through web content without requiring local system access, and the impact extends to the entire system since the heap corruption can be leveraged to execute arbitrary code with the privileges of the affected user. This vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under the T1059.007 command and scripting interpreter category, specifically targeting the use of ActiveX controls for code execution.
The operational impact of CVE-2009-2496 extends beyond simple privilege escalation to encompass complete system compromise and data exfiltration capabilities. Organizations running affected versions of Microsoft Office, ISA Server, or Small Business Accounting software face significant risk when their users browse to malicious websites or open compromised documents containing the vulnerable ActiveX control. The vulnerability affects not just individual systems but entire enterprise networks since ActiveX controls are commonly deployed in corporate environments and web applications. The exploitation process typically involves crafting malicious web content that triggers the vulnerable methods within the Office Web Components ActiveX control, causing the heap buffer overflow that ultimately leads to code execution. This type of vulnerability is particularly dangerous in enterprise environments where users may have elevated privileges and where the attack surface includes both internal and external network boundaries. Organizations should consider this vulnerability as part of a broader attack surface that includes outdated ActiveX controls, which are often overlooked in modern security assessments but remain critical entry points for sophisticated attackers.
Mitigation strategies for CVE-2009-2496 should include immediate patching of affected Microsoft products, as well as network-based protections such as ActiveX control restrictions in web browsers and application whitelisting policies. Microsoft released security updates for all affected versions, and organizations should prioritize deployment of these patches to eliminate the vulnerability at its source. Browser-based mitigations can include disabling ActiveX controls entirely or implementing strict security zones that prevent automatic execution of potentially malicious ActiveX content. Additionally, network administrators should consider implementing web application firewalls and content filtering solutions that can detect and block malicious payloads targeting ActiveX controls. The vulnerability also highlights the importance of maintaining up-to-date software inventories and implementing regular vulnerability assessments that specifically target legacy ActiveX controls and components. Organizations should also consider decommissioning or migrating away from older Office Web Components that are no longer supported, as these legacy components pose ongoing security risks that cannot be fully mitigated through patching alone.