CVE-2010-1247 in Excel
Summary
by MITRE
Unspecified vulnerability in Microsoft Office Excel 2002 SP3 allows remote attackers to execute arbitrary code via an Excel file with a malformed RTD (0x813) record that triggers heap corruption, aka "Excel Memory Corruption Vulnerability," a different vulnerability than CVE-2010-0823 and CVE-2010-1249.
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Analysis
by VulDB Data Team • 09/15/2021
This vulnerability represents a critical memory corruption flaw in Microsoft Office Excel 2002 Service Pack 3 that enables remote code execution through specially crafted Excel files. The vulnerability specifically manifests when the application processes a malformed RTD (Real-Time Data) record with the identifier 0x813, which triggers heap corruption during the parsing of spreadsheet data structures. The flaw resides in how Excel handles the RTD record format, particularly when the record contains invalid or malformed data that causes the application to write beyond allocated memory boundaries. This memory corruption scenario creates exploitable conditions where malicious actors can manipulate the heap memory layout to inject and execute arbitrary code within the context of the Excel application process.
The technical implementation of this vulnerability leverages heap-based buffer overflow mechanisms that are classified under CWE-121 as unsafe use of stack-based buffers and CWE-787 as out-of-bounds write conditions. When Excel encounters the malformed RTD record, the parsing routine fails to properly validate the record structure, leading to memory corruption that can be leveraged for code execution. The vulnerability is particularly dangerous because it can be triggered through legitimate Excel file processing without requiring any special user interaction beyond opening the malicious file, making it a prime candidate for drive-by download attacks. The RTD record format is commonly used in Excel for connecting to external data sources, which means that even seemingly benign spreadsheet files could contain malicious RTD records that exploit this vulnerability.
From an operational perspective, this vulnerability presents significant risk to enterprise environments where Excel 2002 is still in use, as it provides attackers with a reliable method for gaining remote code execution privileges on target systems. The attack vector is particularly concerning because it can be delivered through email attachments, web downloads, or compromised websites, making it difficult to defend against through traditional network security controls. Organizations that have not upgraded from Excel 2002 are particularly vulnerable since this version lacks modern exploit mitigation features such as DEP (Data Execution Prevention) and ASLR (Address Space Layout Randomization) protections that are standard in later Office versions. The vulnerability's classification under the ATT&CK framework would align with technique T1203 as Exploitation for Client Execution, where attackers leverage software vulnerabilities to execute malicious code on target systems.
Mitigation strategies should focus on immediate patching of affected systems with the relevant Microsoft security updates, as well as implementing restrictive file handling policies that limit the execution of Excel files from untrusted sources. Network-based controls such as email filtering and web content filtering should be enhanced to block potentially malicious Excel files, particularly those with embedded RTD records. System administrators should also consider implementing application whitelisting policies that restrict the execution of Office applications in high-risk environments. The vulnerability demonstrates the importance of maintaining up-to-date software patches and highlights the risks associated with legacy software environments that continue to operate without proper security updates. Organizations should also conduct regular vulnerability assessments to identify and remediate similar memory corruption vulnerabilities in other Microsoft Office applications and third-party software that may be similarly affected by heap-based buffer overflow conditions.