CVE-2018-8382 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 • 05/02/2023
The vulnerability identified as CVE-2018-8382 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, indicating a widespread impact across the Microsoft Office ecosystem. The flaw manifests when the application fails to properly handle memory management during certain operations, leading to unintended data exposure. According to CWE-200, this vulnerability maps directly to information exposure through improper handling of memory contents, where sensitive information that should remain confidential becomes accessible to unauthorized parties through memory disclosure mechanisms. The vulnerability falls under the broader category of memory corruption issues that can be exploited to gain insights into system operations and data structures.
The technical implementation of this vulnerability occurs within Excel's memory management subsystem when processing specific file formats or executing certain operations that trigger improper memory handling. When Excel encounters particular data structures or file formats, it may inadvertently expose memory segments containing sensitive information through various access points. This can include data from previous operations, temporary variables, or even cached information from other applications that were running in the same memory space. The flaw typically manifests when Excel attempts to render or process complex spreadsheets containing specific combinations of formulas, data types, or formatting elements that cause memory corruption or improper memory boundary handling. Attackers can potentially exploit this by crafting malicious Excel files that trigger the vulnerability, causing the application to dump memory contents that may include sensitive data from other processes or previous operations.
The operational impact of CVE-2018-8382 extends beyond simple information disclosure, as the exposed memory contents can contain a wide range of sensitive data including user credentials, personal information, business data, and potentially system configuration details. This vulnerability can be particularly dangerous in enterprise environments where Excel is commonly used to process sensitive business documents, financial data, or confidential communications. The exposure of memory contents can potentially lead to credential theft, data breaches, or further exploitation opportunities where attackers can use the disclosed information to craft more sophisticated attacks. From an ATT&CK perspective, this vulnerability aligns with techniques such as credential access and defense evasion, as the information disclosure can provide attackers with data needed for privilege escalation or to avoid detection. The vulnerability also contributes to the broader threat landscape by potentially enabling attackers to gather intelligence about system configurations, user behavior patterns, and organizational data structures.
Mitigation strategies for this vulnerability should focus on both immediate patching and operational security measures. Microsoft has released security updates that address this specific memory handling issue, and organizations should prioritize applying these patches across all affected Microsoft Office installations. Additionally, implementing strict file validation policies, particularly for Excel files received from external sources, can help reduce exploitation risks. Network segmentation and access controls should be reinforced to limit the potential impact of successful exploitation attempts. Organizations should also consider implementing application whitelisting policies that restrict the execution of potentially malicious Excel files. Regular security awareness training for users can help identify suspicious file attachments that may contain malicious code designed to trigger this vulnerability. Monitoring systems should be configured to detect unusual Excel process behavior or memory access patterns that could indicate exploitation attempts. The vulnerability demonstrates the importance of proper memory management in office applications and highlights the need for comprehensive security testing of file processing functions in productivity software.