CVE-2016-7229 in Office
Summary
by MITRE
Microsoft Excel 2007 SP3, Excel 2010 SP2, Excel 2013 SP1, Excel 2013 RT SP1, Excel 2016, Excel for Mac 2011, Excel 2016 for Mac, 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."
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 09/30/2022
The Microsoft Office Memory Corruption Vulnerability identified as CVE-2016-7229 represents a critical security flaw affecting multiple versions of Microsoft Excel across different platforms and operating systems. This vulnerability resides within the parsing mechanisms of Excel's document handling capabilities, specifically when processing malformed or crafted Office documents. The flaw manifests as a memory corruption issue that occurs during the interpretation of certain file structures, creating opportunities for attackers to inject malicious code into the target system. The vulnerability affects a wide range of Excel versions including 2007 SP3, 2010 SP2, 2013 SP1, 2013 RT SP1, 2016, and various Mac versions, indicating a widespread impact across Microsoft's Office suite. The vulnerability is particularly concerning because it allows remote code execution without requiring user interaction beyond opening the malicious document, making it a prime target for phishing campaigns and targeted attacks. The affected systems include both Windows and Mac environments, demonstrating the cross-platform nature of the threat and the need for comprehensive security measures across different operating systems.
The technical exploitation of this vulnerability occurs through the manipulation of memory structures during document parsing operations. When Excel encounters a specially crafted Office document containing malformed data structures, the memory management functions within the application fail to properly validate input parameters, leading to memory corruption. This memory corruption typically manifests as buffer overflows or heap corruption, which can be leveraged by attackers to overwrite critical memory locations and inject executable code. The vulnerability is categorized under CWE-125, which describes "Out-of-bounds Read" conditions, and more specifically aligns with CWE-787, "Out-of-bounds Write," indicating that attackers can write data beyond the boundaries of allocated memory regions. The attack vector is classified as remote, meaning that exploitation can occur through network-based delivery methods such as email attachments, web downloads, or malicious file sharing platforms. The vulnerability's classification under the ATT&CK framework would place it within the T1203 category, representing "Exploitation for Client Execution," and potentially T1059, "Command and Scripting Interpreter," as attackers can leverage the executed code to perform additional malicious activities.
The operational impact of CVE-2016-7229 extends beyond simple code execution, as successful exploitation can result in complete system compromise and persistent access to affected environments. Attackers can leverage this vulnerability to establish backdoors, exfiltrate sensitive data, deploy additional malware, or use the compromised system as a launch point for further attacks within a network. The vulnerability's ability to execute code remotely without user interaction makes it particularly dangerous in enterprise environments where users may inadvertently open malicious documents from email attachments or web downloads. Organizations using affected Excel versions face significant risk of data breaches, system infiltration, and potential lateral movement within their networks. The widespread adoption of Microsoft Office across business environments means that a single compromised system can potentially affect multiple users and departments, creating cascading security failures. The vulnerability's impact is further amplified by the fact that many users may not be aware of the specific Excel versions they are running, making it difficult to assess the full scope of potential exposure.
Mitigation strategies for CVE-2016-7229 should include immediate patch deployment from Microsoft, which addresses the underlying memory corruption issues in the affected Excel versions. Organizations should implement comprehensive network security measures including email filtering, web proxy controls, and file validation systems to prevent malicious documents from reaching end users. The implementation of principle of least privilege access controls can limit the damage if exploitation occurs, while regular security awareness training can help users recognize potential phishing attempts. System administrators should consider disabling unnecessary Office document formats and implementing application whitelisting policies to prevent execution of untrusted code. Additional defensive measures include monitoring for suspicious file access patterns, implementing intrusion detection systems, and maintaining current antivirus signatures that can detect known exploit patterns. The vulnerability's classification as a critical issue by Microsoft underscores the importance of immediate remediation efforts, with patch management procedures prioritized at the highest level of security operations. Organizations should also conduct thorough vulnerability assessments to identify all systems running affected Excel versions and implement layered defense strategies to protect against similar future vulnerabilities.