CVE-2020-0651 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-2020-0650, CVE-2020-0653.
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Analysis
by VulDB Data Team • 03/21/2024
The vulnerability identified as CVE-2020-0651 represents a critical remote code execution flaw in Microsoft Excel software that stems from improper handling of objects within memory structures. This vulnerability specifically affects Microsoft Excel versions including Excel 2016 for Windows, Excel 2019 for Windows, and Microsoft 365 for Windows. The flaw manifests when Excel processes certain file formats or embedded objects that trigger memory corruption conditions, creating opportunities for malicious actors to execute arbitrary code on affected systems. The vulnerability is particularly concerning because it can be exploited through social engineering attacks where users inadvertently open malicious Excel files, making it a prime target for targeted attacks in corporate environments.
From a technical perspective, CVE-2020-0651 falls under the category of memory corruption vulnerabilities and aligns with CWE-125, which describes "Out-of-bounds Read" conditions that can lead to memory corruption and arbitrary code execution. The vulnerability occurs during the parsing and rendering of Excel objects in memory, where insufficient bounds checking allows attackers to manipulate memory pointers and execute malicious code with the privileges of the victim user. This type of vulnerability typically involves heap-based memory corruption where attackers can overwrite critical memory structures or function pointers to redirect execution flow. The flaw operates at the application level rather than the operating system level, making it particularly dangerous because it can bypass many traditional security controls that operate at lower system layers.
The operational impact of CVE-2020-0651 extends beyond simple exploitation to encompass significant business continuity risks and data compromise potential. Organizations utilizing Microsoft Excel in their daily operations face substantial risk of unauthorized access, data exfiltration, and system compromise when this vulnerability exists in their environment. Attackers can leverage this vulnerability to establish persistent backdoors, escalate privileges, and move laterally within networks to access sensitive corporate data. The vulnerability's remote execution capability means that attackers do not require physical access to target systems, enabling large-scale attacks against multiple organizations simultaneously. Security teams must also consider the difficulty in detecting exploitation attempts, as legitimate Excel operations may appear normal while malicious code executes in the background.
Mitigation strategies for CVE-2020-0651 primarily focus on immediate patch management and operational security enhancements. Microsoft released security updates through their regular monthly patch Tuesday releases, which address the memory handling issues in Excel's object parsing routines. Organizations should prioritize immediate deployment of these patches across all affected systems, particularly those with high-value data or critical operations. Additional mitigations include implementing application control policies that restrict Excel's ability to access external resources, disabling macro execution in Excel, and employing sandboxing technologies to isolate Excel processes from critical system resources. Network security controls such as email filtering and web proxy configurations can help prevent users from accessing malicious Excel files through phishing campaigns. The vulnerability also highlights the importance of regular security assessments and penetration testing to identify similar memory corruption issues in other Microsoft Office applications and third-party software that may be equally vulnerable to exploitation.