CVE-2007-0033 in Office
Summary
by MITRE
Microsoft Outlook 2002 and 2003 allows user-assisted remote attackers to execute arbitrary code via a malformed VEVENT record in an .iCal meeting request or ICS file.
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Analysis
by VulDB Data Team • 01/12/2025
Microsoft Outlook 2002 and 2003 applications contain a critical buffer overflow vulnerability in their handling of iCalendar (.ics) file formats that enables remote code execution when processing malformed VEVENT records. This vulnerability resides in the parsing logic that processes calendar meeting requests and appointment data, specifically when Outlook encounters improperly formatted iCalendar data structures. The flaw occurs during the interpretation of VEVENT components within iCalendar files, where insufficient input validation allows attackers to craft malicious calendar invitations that trigger memory corruption when the application attempts to parse and display the malformed data. The vulnerability is classified as user-assisted remote code execution since it requires user interaction to open the malicious iCalendar file, making it particularly dangerous in corporate environments where calendar sharing is common. This issue falls under CWE-121, which describes heap-based buffer overflow conditions, and aligns with ATT&CK technique T1059.007 for command and script interpreter execution through Office applications. The attack vector typically involves sending specially crafted iCalendar meeting requests via email that, when opened in Outlook, cause the application to crash and potentially execute malicious code with the privileges of the logged-in user. The vulnerability represents a significant risk in enterprise environments where Outlook is widely used and calendar sharing is prevalent. When exploited, this flaw can allow attackers to gain unauthorized access to systems, escalate privileges, and potentially establish persistent backdoors. The vulnerability affects both Outlook 2002 and 2003 versions, which were widely deployed in corporate networks during the early 2000s, making it particularly dangerous as these applications were commonly used for scheduling and collaboration. Microsoft addressed this vulnerability through security updates that improved input validation and memory management within the iCalendar parsing components. Organizations should prioritize patching affected systems and implementing email filtering policies to prevent the delivery of potentially malicious calendar files. Additional mitigations include disabling automatic calendar processing, educating users about the risks of opening untrusted calendar invitations, and implementing network-based security controls to monitor and block suspicious iCalendar data transfers. The vulnerability demonstrates the importance of proper input validation in calendar and scheduling applications, as well as the need for comprehensive security testing of file format parsers in enterprise applications. This flaw underscores the critical nature of securing collaborative software platforms where users frequently exchange data files that may contain embedded malicious content. The attack scenario typically requires social engineering to convince users to open malicious calendar invitations, making user awareness training an essential component of defense strategies. Security professionals should consider this vulnerability when assessing the security posture of legacy Microsoft Office installations and ensure that proper security measures are in place to protect against similar issues in other calendar and scheduling applications. The vulnerability also highlights the need for regular security assessments of enterprise collaboration tools to identify and remediate potential code execution flaws that could be exploited by threat actors.