CVE-2016-7231 in Office
Summary
by MITRE
Microsoft Excel 2007 SP3, Excel for Mac 2011, Office Compatibility Pack SP3, and Excel Viewer allow remote attackers to execute arbitrary code via a crafted Office document, aka "Microsoft Office Memory Corruption Vulnerability."
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Analysis
by VulDB Data Team • 09/30/2022
The Microsoft Office Memory Corruption Vulnerability identified as CVE-2016-7231 represents a critical security flaw affecting multiple versions of Microsoft Excel and related Office components. This vulnerability resides within the memory management systems of these applications, specifically when processing crafted Office documents that contain malformed data structures. The flaw manifests during the parsing and rendering of spreadsheet files, creating opportunities for attackers to manipulate memory regions and execute malicious code with the privileges of the targeted user.
This vulnerability operates through a classic buffer overflow or memory corruption mechanism where the affected Excel applications fail to properly validate input data from maliciously crafted files. When users open or even preview these specially constructed documents, the application's memory handling routines become compromised, allowing attackers to overwrite critical memory locations and redirect program execution flow. The vulnerability is particularly dangerous because it can be exploited through social engineering attacks where users unknowingly open malicious files, making it a prime target for phishing campaigns and targeted attacks. The flaw affects not only the Windows versions of Excel 2007 SP3 and the Office Compatibility Pack SP3 but also extends to Excel for Mac 2011, demonstrating the cross-platform nature of the vulnerability.
The operational impact of CVE-2016-7231 is severe and multifaceted, as it provides attackers with arbitrary code execution capabilities that can lead to complete system compromise. Once successfully exploited, the vulnerability allows attackers to install malware, steal sensitive data, establish persistence mechanisms, and potentially escalate privileges within the compromised environment. The attack vector is particularly insidious because it requires minimal user interaction beyond opening the malicious document, making it highly effective for widespread exploitation. Security researchers have categorized this vulnerability under CWE-125, which describes "Out-of-bounds Read" conditions that can lead to memory corruption, and it aligns with ATT&CK techniques such as T1203 for Exploitation for Client Execution and T1059 for Command and Scripting Interpreter, as attackers can leverage the vulnerability to execute arbitrary commands and establish persistent access.
Mitigation strategies for CVE-2016-7231 must include immediate patch deployment from Microsoft, as the company released security updates specifically addressing this memory corruption flaw in their regular security bulletins. Organizations should implement strict document handling policies that restrict opening of Office files from untrusted sources, particularly those received via email attachments or downloaded from unknown websites. Network-based protections such as email filtering systems and web proxies should be configured to block Office document attachments from suspicious domains or with known malicious patterns. Additionally, users should be trained to recognize phishing attempts and avoid opening unexpected Office files, while system administrators should monitor for unusual network activity or file access patterns that might indicate exploitation attempts. The vulnerability also underscores the importance of maintaining up-to-date security software and implementing defense-in-depth strategies that combine multiple layers of protection to prevent successful exploitation of memory corruption vulnerabilities.