CVE-2011-1275 in Excel
Summary
by MITRE
Microsoft Excel 2002 SP3; Office 2004, 2008, and 2011 for Mac; and Open XML File Format Converter for Mac do not properly validate record information during parsing of Excel spreadsheets, which allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted spreadsheet, aka "Excel Memory Heap Overwrite Vulnerability."
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Analysis
by VulDB Data Team • 11/09/2021
The vulnerability identified as CVE-2011-1275 represents a critical memory corruption flaw affecting multiple versions of Microsoft Excel and related Office applications across both Windows and Mac platforms. This vulnerability stems from inadequate validation of record information during the parsing process of Excel spreadsheet files, creating a pathway for malicious actors to exploit the software's memory management mechanisms. The issue specifically impacts Excel 2002 SP3, Office 2004, 2008, and 2011 for Mac, along with the Open XML File Format Converter for Mac, making it a widespread concern across Microsoft's Office suite ecosystem.
The technical nature of this vulnerability falls under CWE-125, which describes "Out-of-bounds Read" conditions where applications access memory locations beyond the intended boundaries. During the parsing of Excel files, the affected applications fail to properly validate the structure and length of records within the spreadsheet format, allowing attackers to craft malicious files that trigger heap memory overwrite conditions. When these malformed records are processed, the application's memory management routines become corrupted, leading to unpredictable behavior that can be exploited to execute arbitrary code or cause system crashes. The vulnerability manifests as a heap buffer overflow, where attacker-controlled data is written beyond the allocated memory boundaries, potentially overwriting critical program structures or executable code.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it provides remote attackers with the capability to achieve arbitrary code execution on affected systems. This represents a significant security risk in enterprise environments where users may inadvertently open malicious Excel files through phishing attacks, malicious attachments, or compromised web downloads. The vulnerability can be exploited through various attack vectors including email attachments, web-based document sharing, or compromised websites that serve malicious Excel files. Once successfully exploited, the malicious code could potentially escalate privileges, establish persistent backdoors, or exfiltrate sensitive data from the compromised system.
Mitigation strategies for CVE-2011-1275 should encompass both immediate patch deployment and operational security measures. Microsoft released security updates addressing this vulnerability, and organizations must ensure all affected systems receive these patches promptly. Additionally, implementing strict file validation policies, disabling automatic execution of Office files from untrusted sources, and deploying email filtering solutions can significantly reduce the risk of exploitation. Network segmentation and endpoint protection solutions should be configured to monitor for suspicious file execution patterns, while regular security awareness training can help users recognize potential phishing attempts that might deliver malicious Excel files. The vulnerability demonstrates the importance of proper input validation and memory safety practices in software development, aligning with ATT&CK technique T1059.005 for command and scripting interpreter usage, as exploitation often involves executing malicious code through compromised Office applications.