CVE-2018-0806 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 Remote Code Execution Vulnerability". This CVE is unique from CVE-2018-0804, CVE-2018-0805, and CVE-2018-0807.
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Analysis
by VulDB Data Team • 01/29/2021
The vulnerability identified as CVE-2018-0806 represents a critical remote code execution flaw within Microsoft Office's Equation Editor component across multiple versions including Office 2003 through Office 2016. This vulnerability specifically targets the manner in which the Equation Editor processes objects in memory, creating a pathway for attackers to execute arbitrary code on affected systems. The flaw resides in the way the application handles mathematical equation objects that are embedded within Word documents, making it particularly dangerous as it can be exploited through routine document processing activities. The vulnerability's classification under the Microsoft Word Remote Code Execution Vulnerability designation indicates its potential to allow attackers to gain complete control over victim systems without requiring user interaction beyond opening a malicious document.
The technical exploitation of this vulnerability occurs when a maliciously crafted document containing specially constructed Equation Editor objects is opened by an affected Office version. The flaw stems from improper memory handling during the parsing of these mathematical objects, which allows attackers to manipulate memory structures and execute malicious code with the privileges of the affected user. This type of vulnerability is classified as a buffer overflow or memory corruption issue, and aligns with CWE-125: "Out-of-bounds Read" and CWE-787: "Out-of-bounds Write" in the Common Weakness Enumeration catalog. The attack vector leverages the Equation Editor's object handling mechanism, where insufficient input validation and memory boundary checks enable attackers to overwrite memory locations and redirect execution flow. This particular vulnerability demonstrates a classic software security flaw where improper bounds checking during object deserialization leads to arbitrary code execution.
The operational impact of CVE-2018-0806 extends beyond simple remote code execution, as it provides attackers with persistent access to compromised systems and enables further lateral movement within networks. Once exploited, attackers can establish backdoors, escalate privileges, and deploy additional malware payloads. The vulnerability's presence in multiple Office versions from 2003 to 2016 means that organizations with legacy systems remain at risk, particularly those that have not implemented proper patch management protocols. The flaw's similarity to other vulnerabilities in the same CVE family including CVE-2018-0804, CVE-2018-0805, and CVE-2018-0807 suggests a broader pattern of memory handling issues within Microsoft Office's Equation Editor component, indicating that the underlying architectural problems may have been systemic rather than isolated incidents. Organizations using these affected versions face significant risk exposure, particularly in environments where users frequently open documents from untrusted sources.
Mitigation strategies for CVE-2018-0806 should prioritize immediate patch deployment from Microsoft, as the company released security updates specifically addressing this vulnerability. System administrators should implement strict document filtering policies, particularly for documents containing Equation Editor objects, and consider disabling Equation Editor functionality in production environments where possible. Network segmentation and endpoint protection solutions can provide additional layers of defense, while user education about suspicious document attachments remains crucial. The vulnerability's exploitation typically requires no user interaction beyond document opening, making it particularly dangerous in targeted attacks where social engineering might be employed to deliver malicious documents. Organizations should also implement monitoring for unusual network traffic patterns and system behavior that might indicate exploitation attempts, as the ATT&CK framework categorizes this type of vulnerability exploitation under T1059: "Command and Scripting Interpreter" and T1078: "Valid Accounts" for lateral movement and persistence phases of attack operations. Regular security assessments and vulnerability scanning should be conducted to identify systems running unsupported Office versions that remain vulnerable to this and similar memory corruption attacks.