CVE-2016-0035 in Excel
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."
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Analysis
by VulDB Data Team • 06/21/2018
This vulnerability represents a critical memory corruption flaw affecting multiple versions of Microsoft Excel software across different platforms and operating systems. The vulnerability arises from improper handling of malformed Office document structures during the parsing process, specifically when Excel attempts to process crafted spreadsheet files. The flaw exists in the way the application manages memory allocation and data processing when encountering specially crafted input data within Office documents. Attackers can exploit this weakness by preparing malicious Office files that trigger unexpected behavior in Excel's processing engine, leading to arbitrary code execution on the target system.
The technical nature of this vulnerability aligns with common software security weaknesses categorized under CWE-125, which describes out-of-bounds read conditions that can lead to memory corruption. The vulnerability manifests as a heap-based buffer overflow or similar memory management issue that occurs when Excel attempts to parse malformed data structures within the Office document format. This type of memory corruption vulnerability is particularly dangerous because it can be leveraged to execute arbitrary code with the privileges of the user running the affected application. The exploitation process typically involves crafting a specific Office document containing malicious payload data that, when opened by the vulnerable Excel version, triggers the memory corruption and allows remote code execution.
From an operational perspective, this vulnerability presents significant risk to enterprise environments where users frequently open Office documents from untrusted sources. The attack vector is particularly insidious because it requires no user interaction beyond opening the malicious document, making it susceptible to phishing campaigns and social engineering attacks. The vulnerability affects widely deployed software versions across multiple platforms including Windows, Mac OS, and various Office compatibility packs, amplifying its potential impact. Organizations with extensive Excel usage patterns face heightened risk as users may unknowingly trigger the vulnerability through routine document opening activities, especially in environments where document sharing occurs frequently.
The exploitation of CVE-2016-0035 aligns with tactics documented in the MITRE ATT&CK framework under the Tactic of Execution and Persistence. Attackers can leverage this vulnerability to establish initial access and potentially maintain persistent presence within compromised systems. The vulnerability's impact extends beyond simple code execution to include potential privilege escalation scenarios where the attacker might gain elevated system privileges. Security professionals should note that this vulnerability was part of a broader class of Office-based exploits that targeted memory corruption flaws in Microsoft's productivity suite. The affected versions span multiple product lines and service packs, indicating that the vulnerability was a fundamental flaw in the document processing architecture that required comprehensive patching across all supported platforms. Organizations should implement layered defenses including email filtering, user education, and application whitelisting to mitigate the risk of exploitation, while ensuring all systems receive timely security updates from Microsoft to address this and related vulnerabilities in their Office applications.