CVE-2018-8429 in Excel
Summary
by MITRE
An information disclosure vulnerability exists when Microsoft Excel improperly discloses the contents of its memory, aka "Microsoft Excel Information Disclosure Vulnerability." This affects Microsoft Excel Viewer, Microsoft Office, Microsoft Excel.
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Analysis
by VulDB Data Team • 05/08/2023
The vulnerability identified as CVE-2018-8429 represents a critical information disclosure flaw within Microsoft Excel applications that can potentially expose sensitive data stored in memory. This vulnerability affects multiple Microsoft Office products including Excel Viewer, Microsoft Office suite, and Excel itself, making it a widespread concern across various deployment scenarios. The issue stems from improper memory handling mechanisms within the Excel application that fail to adequately protect sensitive information from being inadvertently exposed through memory contents. According to CWE-200, this vulnerability falls under the category of "Information Exposure" where the application unintentionally reveals sensitive data to unauthorized parties. The flaw manifests when Excel processes certain file formats or operations that trigger memory access patterns which can be exploited to extract confidential information from the application's memory space.
The technical exploitation of this vulnerability occurs through memory corruption or improper memory management during Excel's processing of specific file structures or commands. Attackers can potentially leverage this flaw to access sensitive information that should remain protected within the application's memory boundaries. This type of information disclosure can include but is not limited to user data, document contents, temporary files, or other sensitive information that Excel might store in memory during processing operations. The vulnerability is particularly concerning because it operates at the memory level rather than through network-based attacks, making it more difficult to detect and prevent through traditional network security measures. The attack vector typically involves crafting malicious Excel files or manipulating existing documents in ways that trigger the vulnerable memory handling code paths.
The operational impact of CVE-2018-8429 extends beyond simple data exposure, as it can potentially enable more sophisticated attacks that build upon the initial information disclosure. Organizations using Microsoft Excel in environments with sensitive data are particularly at risk, as this vulnerability could lead to unauthorized access to confidential business information, financial records, personal data, or proprietary documents. The vulnerability affects both end-user systems and enterprise environments where Excel is commonly used for data analysis, report generation, and document sharing. Security professionals must consider this vulnerability when assessing risk in Microsoft Office deployments, particularly in scenarios involving untrusted document handling or when users interact with external sources. The potential for privilege escalation exists if the disclosed information can be used to further compromise the system or gain access to additional resources within the network environment.
Mitigation strategies for this vulnerability should include immediate deployment of Microsoft security patches and updates that address the memory handling flaws in affected Excel versions. Organizations should implement strict document validation procedures, particularly for files received from external sources or untrusted parties, and consider deploying sandboxing solutions to isolate Excel processes from critical system resources. Network administrators should monitor for suspicious file access patterns and implement security controls that prevent automatic execution of potentially malicious Excel files. The vulnerability aligns with ATT&CK technique T1059 which involves executing malicious code through legitimate system tools, and T1068 which covers privilege escalation techniques that could leverage information disclosure vulnerabilities. Regular security awareness training for users should emphasize the dangers of opening untrusted Excel files and the importance of keeping Microsoft Office applications updated with the latest security patches. System administrators should also consider implementing application whitelisting policies that restrict execution of unauthorized Excel-related processes and monitor for anomalous memory access patterns that might indicate exploitation attempts.