CVE-2018-0812 in Word
Summary
by MITRE
Equation Editor in Microsoft Office 2003, Microsoft Office 2007, Microsoft Office 2010, Microsoft Office 2013, and Microsoft Office 2016 allows a remote code execution vulnerability due to the way objects are handled in memory, aka "Microsoft Word Memory Corruption Vulnerability".
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Analysis
by VulDB Data Team • 01/29/2021
The vulnerability identified as CVE-2018-0812 represents a critical memory corruption flaw within Microsoft Office's Equation Editor component affecting multiple versions from 2003 through 2016. This vulnerability stems from improper handling of objects within memory structures, creating opportunities for remote code execution attacks that can compromise entire systems. The Equation Editor serves as a mathematical equation input tool within Microsoft Office applications, making it a common target for attackers seeking to exploit office productivity software. This flaw operates at a fundamental level where the software fails to properly validate or sanitize object references during memory operations, leading to potential buffer overflows or memory corruption scenarios that adversaries can manipulate for malicious purposes.
The technical nature of this vulnerability places it squarely within CWE-125, which describes out-of-bounds read conditions, and CWE-787, which covers out-of-bounds write operations. These classifications reflect the core issue where memory boundaries are exceeded during object processing within the Equation Editor. The flaw manifests when the vulnerable software processes specially crafted malicious objects that trigger memory corruption during rendering or evaluation of mathematical equations. Attackers can exploit this by embedding malicious content within Office documents, particularly those containing Equation Editor objects, which when opened trigger the vulnerable code path. The memory corruption occurs during the processing of equation objects, where the software fails to properly validate input parameters before allocating or accessing memory regions, creating potential for arbitrary code execution.
The operational impact of CVE-2018-0812 extends beyond simple system compromise, as it aligns with several tactics described in the MITRE ATT&CK framework under T1059 for command and control execution and T1203 for exploitation for privilege escalation. Organizations running affected Microsoft Office versions face significant risk exposure since Equation Editor objects can be embedded in various document formats including doc, docx, xls, xlsx, and ppt files. The vulnerability enables attackers to execute malicious code with the privileges of the user who opens the compromised document, potentially leading to full system compromise. This makes the flaw particularly dangerous in enterprise environments where users frequently open documents from external sources or untrusted networks. The remote execution capability means that adversaries can exploit this vulnerability without requiring physical access to target systems, making it a prime candidate for widespread exploitation campaigns.
Mitigation strategies for this vulnerability should prioritize immediate patching of affected Microsoft Office versions through official security updates from Microsoft, as the company has released specific patches addressing this memory corruption issue. Organizations should implement strict document filtering policies that restrict the opening of Office documents from untrusted sources, particularly those containing Equation Editor objects. Network-based security controls including email filtering systems and web proxies should be configured to block potentially malicious Office documents before they reach end users. Additionally, security awareness training programs should educate users about the risks of opening unexpected Office documents, especially those received via email or downloaded from untrusted websites. System hardening measures such as disabling Equation Editor functionality in enterprise environments where it is not required, implementing application whitelisting policies, and maintaining regular backup procedures can further reduce the risk exposure associated with this vulnerability. The vulnerability also underscores the importance of maintaining up-to-date security patches and implementing layered defense strategies to protect against similar memory corruption flaws that may exist in other software components.