CVE-2019-0669 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'.
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Analysis
by VulDB Data Team • 05/13/2020
The vulnerability identified as CVE-2019-0669 represents a critical information disclosure flaw within Microsoft Excel that stems from improper memory handling during specific computational operations. This vulnerability falls under the broader category of memory corruption issues that can lead to unauthorized data exposure, making it particularly concerning for enterprise environments where sensitive financial and operational data are routinely processed within Excel applications. The flaw manifests when Excel encounters certain data processing scenarios that cause it to inadvertently expose memory contents through various channels including file corruption, application crashes, or unexpected data rendering behaviors that reveal previously stored information.
Technical analysis reveals that the vulnerability occurs during Excel's handling of complex data structures and calculations where memory management fails to properly sanitize or isolate sensitive data segments. This improper memory disclosure can potentially expose confidential information such as passwords, personal identification numbers, business strategies, financial reports, or other sensitive data that may have been temporarily stored in memory during processing operations. The vulnerability is particularly dangerous because it can be triggered through seemingly benign spreadsheet operations, making it difficult for users to recognize when their data is at risk. According to CWE classification, this represents a memory exposure vulnerability categorized under CWE-200, which specifically addresses information exposure through improper handling of sensitive data within application memory spaces.
The operational impact of CVE-2019-0669 extends beyond simple data leakage, as it creates potential attack vectors for sophisticated adversaries who may leverage this weakness to gain unauthorized access to sensitive corporate or personal information. Attackers could potentially exploit this vulnerability by crafting malicious Excel files or manipulating existing spreadsheets in ways that trigger the memory disclosure behavior, leading to information extraction from compromised systems. This vulnerability particularly affects organizations using older versions of Microsoft Office, where the memory management mechanisms have not been properly updated to prevent such exposure scenarios. The risk is amplified in environments where Excel is frequently used to process sensitive data, including financial institutions, government agencies, and enterprises handling proprietary business information.
Security professionals should consider this vulnerability in the context of broader attack frameworks such as those outlined in the MITRE ATT&CK matrix, specifically categorizing it under techniques related to credential access and information gathering. The vulnerability's exploitation potential aligns with ATT&CK technique T1003, which covers credential dumping, as sensitive information exposed through memory disclosure could include authentication tokens or other credentials that might be leveraged for further system compromise. Organizations should implement comprehensive patch management strategies to address this vulnerability, ensuring that all Microsoft Office installations receive the necessary updates from Microsoft Security Response Center. Additionally, implementing network monitoring solutions that can detect unusual memory access patterns or file corruption behaviors may provide early warning capabilities for potential exploitation attempts. Regular security awareness training for end users about the dangers of opening untrusted Excel files and maintaining strict access controls on sensitive data sources can significantly reduce the risk of successful exploitation.