CVE-2019-1110 in Excel
Summary
by MITRE
A remote code execution vulnerability exists in Microsoft Excel software when the software fails to properly handle objects in memory, aka 'Microsoft Excel Remote Code Execution Vulnerability'. This CVE ID is unique from CVE-2019-1111.
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Analysis
by VulDB Data Team • 07/02/2020
The vulnerability identified as CVE-2019-1110 represents a critical remote code execution flaw within Microsoft Excel software that stems from improper handling of objects in memory. This vulnerability specifically affects Microsoft Excel applications running on various Windows operating systems and poses significant security risks to organizations relying on spreadsheet processing capabilities. The flaw manifests when Excel encounters specially crafted malicious files or objects that trigger unexpected memory management behaviors, creating opportunities for attackers to execute arbitrary code on affected systems. Security researchers have classified this as a memory corruption vulnerability that can be exploited remotely without requiring user interaction, making it particularly dangerous in enterprise environments where Excel is commonly used for data processing and analysis tasks.
The technical nature of this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions that occur when software accesses memory locations beyond the intended boundaries. In the context of Excel, this manifests when the application fails to properly validate or sanitize objects stored in memory during processing operations. Attackers can leverage this weakness by crafting malicious Excel files that contain malformed objects or structures designed to trigger buffer overflows or memory corruption during normal processing operations. The vulnerability operates at the memory management level where Excel's internal object handling mechanisms do not adequately protect against maliciously constructed data that can cause the application to execute unintended code paths. This type of vulnerability is particularly insidious because it can be triggered through legitimate file processing operations, making detection and prevention challenging for security teams.
The operational impact of CVE-2019-1110 extends beyond simple remote code execution to encompass broader security implications for enterprise networks and individual workstations. Organizations utilizing Microsoft Excel for business operations face potential compromise of their entire computing infrastructure when this vulnerability is exploited, as successful exploitation can lead to full system compromise and persistence mechanisms. The vulnerability's remote execution capability means that attackers can deploy malicious payloads without requiring physical access to target systems, enabling large-scale attacks across networked environments. According to ATT&CK framework category T1059, this vulnerability facilitates command and control operations through remote code execution, while also supporting T1078 for legitimate credentials use and T1566 for initial access through spearphishing or malicious file delivery. The attack surface is particularly broad given that Excel is widely used across different departments and user roles, increasing the probability of successful exploitation.
Mitigation strategies for CVE-2019-1110 should encompass both immediate patch deployment and defensive operational measures. Microsoft released security updates addressing this vulnerability through their regular patching schedule, and organizations must prioritize immediate deployment of these patches to protect their systems. Additionally, implementing application whitelisting controls can help prevent execution of unauthorized Excel files, while network monitoring should focus on detecting suspicious file transfers or connections to known malicious domains. Security teams should also consider implementing email filtering solutions that can identify and block malicious Excel files before they reach end users, particularly focusing on file types with known exploitation patterns. The vulnerability's characteristics make it suitable for targeted attacks, so organizations should enhance their threat hunting capabilities to detect potential exploitation attempts. Regular security awareness training for end users regarding suspicious email attachments and file downloads remains critical, as social engineering components often complement technical exploits in successful attack scenarios.