CVE-2008-4253 in Visual Basic
Summary
by MITRE
The FlexGrid ActiveX control in Microsoft Visual Basic 6.0, Visual FoxPro 8.0 SP1 and 9.0 SP1 and SP2, Office FrontPage 2002 SP3, and Office Project 2003 SP3 does not properly handle errors during access to incorrectly initialized objects, which allows remote attackers to execute arbitrary code via a crafted HTML document, related to corruption of the "system state," aka "FlexGrid Control Memory Corruption Vulnerability."
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Analysis
by VulDB Data Team • 08/21/2019
The CVE-2008-4253 vulnerability represents a critical memory corruption flaw within Microsoft FlexGrid ActiveX controls that affected multiple Microsoft products including Visual Basic 6.0, Visual FoxPro 8.0 and 9.0, Office FrontPage 2002 SP3, and Office Project 2003 SP3. This vulnerability operates at the core of how these ActiveX components handle error conditions when encountering improperly initialized objects, creating a pathway for remote code execution through maliciously crafted HTML documents. The flaw specifically exploits the system state corruption that occurs during error handling processes, making it particularly dangerous as it can be triggered without user interaction beyond visiting a compromised webpage. The vulnerability is classified under CWE-125 as an out-of-bounds read condition, which is a common vector for memory corruption exploits and aligns with ATT&CK technique T1203 for legitimate program exploitation.
The technical implementation of this vulnerability stems from improper error handling mechanisms within the FlexGrid ActiveX control's object initialization process. When the control encounters malformed or incorrectly structured data during object access, the error handling routine fails to properly manage memory allocation and deallocation, resulting in memory corruption that can be leveraged by attackers. This memory corruption manifests when the system attempts to access memory locations beyond the intended object boundaries, creating opportunities for arbitrary code execution. The vulnerability is particularly insidious because it operates within the context of web browsers that have these ActiveX controls installed, allowing attackers to craft HTML documents that trigger the corrupted system state through embedded malicious content. The exploitation typically requires a user to view a specially crafted webpage that contains the malicious FlexGrid control implementation, making it a prime example of a client-side attack vector.
The operational impact of CVE-2008-4253 extends beyond simple code execution as it provides attackers with the ability to gain full control over affected systems. This vulnerability can be weaponized to deliver malware payloads, establish persistent backdoors, or perform privilege escalation attacks within the victim's environment. The widespread installation of these Microsoft products across enterprise networks and desktop environments created a substantial attack surface that made this vulnerability particularly attractive to threat actors. Organizations running vulnerable versions of Visual Basic, Visual FoxPro, or Office products were at significant risk, as a single compromised webpage could potentially compromise entire networks. The vulnerability's classification as a remote code execution flaw places it within the high-risk category of security issues that can be exploited without requiring physical access to target systems, making it a preferred vector for automated attacks and exploit kits.
Mitigation strategies for CVE-2008-4253 should focus on both immediate remediation and long-term security posture improvements. Microsoft released patches and updates for affected versions of the vulnerable software, which should be deployed immediately to protect systems from exploitation. Organizations should implement ActiveX control restrictions through Group Policy settings or browser security configurations to prevent automatic execution of potentially malicious ActiveX components. Network-based mitigations such as web application firewalls and content filtering solutions can help detect and block malicious HTML content containing vulnerable FlexGrid controls. Additionally, user education and awareness programs should emphasize the dangers of visiting untrusted websites and opening suspicious email attachments that may contain malicious HTML documents. The vulnerability highlights the importance of maintaining up-to-date software patches and implementing defense-in-depth strategies that reduce the attack surface available to potential adversaries. Security teams should also consider implementing monitoring solutions that can detect unusual memory access patterns or system state corruption that may indicate exploitation attempts.