CVE-2010-3235 in Excel
Summary
by MITRE
Microsoft Excel 2002 SP3 does not properly validate formula information, which allows remote attackers to execute arbitrary code via a crafted Excel document, aka "Formula Biff Record Vulnerability."
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 09/26/2021
The CVE-2010-3235 vulnerability represents a critical buffer overflow flaw in Microsoft Excel 2002 Service Pack 3 that stems from inadequate validation of formula data within BIFF (Binary Interchange File Format) records. This vulnerability specifically affects the parsing mechanism that processes formula information contained within Excel files, creating an exploitable condition where maliciously crafted formula records can trigger unauthorized code execution on vulnerable systems. The flaw exists in the way Excel handles the Biff record structure, particularly when processing formula-related data that exceeds expected boundaries, allowing attackers to overwrite memory locations and potentially execute arbitrary code with the privileges of the affected user.
The technical exploitation of this vulnerability leverages the improper handling of formula Biff records during Excel's file parsing process, which falls under CWE-121, heap-based buffer overflow, and CWE-787, out-of-bounds write. Attackers can craft malicious Excel documents containing specially formatted formula records that cause the application to write data beyond the allocated memory buffer, leading to memory corruption that can be exploited to redirect program execution flow. The vulnerability is particularly dangerous because it operates within the context of a legitimate application, making detection more challenging and allowing attackers to leverage the trust relationship between the user and Excel application. This exploit requires no special privileges to initiate the attack, as it targets the application itself rather than system-level components.
The operational impact of CVE-2010-3235 extends beyond simple code execution to encompass potential complete system compromise, especially when combined with other attack vectors or when users open malicious files with elevated privileges. The vulnerability enables attackers to perform actions such as installing malware, modifying system files, accessing sensitive data, or establishing persistent access to compromised systems. From an adversary perspective, this vulnerability aligns with ATT&CK technique T1059.005, executing malicious code through office applications, and T1133, external remote services, as attackers can deliver malicious Excel files through email attachments or web-based delivery mechanisms. The attack surface is broad since Excel is widely used across enterprise environments, making this vulnerability particularly attractive to threat actors seeking mass impact.
Mitigation strategies for CVE-2010-3235 should include immediate deployment of Microsoft security patches and updates, as well as implementing restrictive file handling policies that limit the opening of Excel files from untrusted sources. Organizations should consider disabling automatic execution of macros and implementing application whitelisting to prevent unauthorized code execution. Network-based protections such as email filtering and web proxy configurations can help prevent delivery of malicious Excel files to end users. Additionally, regular security awareness training for employees regarding suspicious email attachments and the risks associated with opening files from unknown sources remains crucial. The vulnerability demonstrates the importance of proper input validation and memory management practices in software development, highlighting how seemingly minor flaws in data parsing can result in severe security consequences. Organizations should also consider implementing endpoint protection solutions that can detect and block exploitation attempts targeting known vulnerabilities like CVE-2010-3235.