CVE-2016-7265 in Office
Summary
by MITRE
Microsoft Excel 2007 SP3, Excel 2010 SP2, Excel 2013 SP1, Excel 2013 RT SP1, Excel 2016, Office Compatibility Pack SP3, Excel Viewer, Excel Services on SharePoint Server 2007 SP3, and Excel Services on SharePoint Server 2010 SP2 allow remote attackers to obtain sensitive information from process memory or cause a denial of service (out-of-bounds read) via a crafted document, aka "Microsoft Office Information Disclosure Vulnerability."
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Analysis
by VulDB Data Team • 10/08/2022
The vulnerability described in CVE-2016-7265 represents a critical information disclosure flaw affecting multiple versions of Microsoft Excel and related Office components. This vulnerability manifests as an out-of-bounds read condition that occurs when processing specially crafted Excel documents, allowing attackers to potentially access sensitive data from process memory or trigger denial of service conditions. The flaw affects a broad range of Microsoft Office products including Excel 2007 through Excel 2016, along with the Office Compatibility Pack and Excel Viewer applications. The vulnerability is particularly concerning because it can be exploited remotely through maliciously crafted documents, making it a significant threat to enterprise environments where Office documents are frequently shared and opened.
The technical root cause of this vulnerability lies in insufficient input validation within Excel's parsing routines for specific file formats. When Excel encounters malformed or specially constructed spreadsheet files, the application fails to properly bounds-check memory access operations, leading to unauthorized memory reads. This type of vulnerability falls under CWE-129, which specifically addresses insufficient validation of length of inputs, and can be classified as a memory safety issue. The out-of-bounds read condition allows attackers to potentially extract sensitive information from adjacent memory locations, including cryptographic keys, passwords, or other confidential data that may be stored in the process memory space. The vulnerability can be exploited through various attack vectors including email attachments, malicious websites, or compromised documents shared through collaboration platforms.
The operational impact of CVE-2016-7265 extends beyond simple information disclosure, as it can lead to significant security consequences for affected organizations. In practical attack scenarios, adversaries can leverage this vulnerability to perform reconnaissance activities, gathering sensitive information that could aid in subsequent attacks targeting the same systems or users. The potential for denial of service makes this vulnerability particularly dangerous in enterprise environments where Excel is frequently used for business-critical operations, as it could disrupt normal business processes or make systems unavailable to legitimate users. Organizations using Excel Services on SharePoint Server 2007 and 2010 are especially vulnerable, as the attack surface expands to include web-based document processing environments where users may not be aware of the security risks associated with opening external documents.
The exploitation of this vulnerability aligns with several tactics described in the MITRE ATT&CK framework, particularly those related to initial access and privilege escalation. Attackers may use this vulnerability as part of a broader attack chain, leveraging the information disclosure to gather intelligence about target systems or users before attempting more sophisticated attacks. The vulnerability's remote exploitability means that organizations cannot rely solely on network segmentation or user education as complete defenses, since the attack can occur without user interaction once a malicious document is opened. Microsoft's security advisory recommends immediate deployment of patches and updates, while organizations should also implement additional security measures such as document validation policies, sandboxing of document processing, and monitoring for unusual memory access patterns or denial of service indicators. The vulnerability underscores the importance of maintaining up-to-date security patches and implementing layered security approaches to protect against sophisticated threats that target widely used productivity applications like Microsoft Excel.