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CVE-2025-53759: Microsoft Office Excel Uninitialized Resource Execution Vulnerability

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Overview

CVE-2025-53759 is a serious vulnerability that affects Microsoft Office Excel, a widely-used spreadsheet software. This flaw allows unauthorized attackers to execute code locally on the victim’s system, leading to potential system compromise or data leakage. Given the widespread use of Excel in organizations across various sectors, this vulnerability poses a significant risk. Its successful exploitation could result in severe business disruption or even financial loss.

Vulnerability Summary

CVE ID: CVE-2025-53759
Severity: High (7.8 CVSS Score)
Attack Vector: Local
Privileges Required: None
User Interaction: Required
Impact: Unauthorized code execution, potential system compromise, or data leakage

Affected Products

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Product | Affected Versions

Microsoft Office Excel | All versions before the patch

How the Exploit Works

The exploit works by taking advantage of an uninitialized resource within Microsoft Office Excel. An attacker crafts a malicious Excel file containing specially designed code. Once the victim opens this file, the code is executed locally on the victim’s machine due to the software’s failure to properly initialize a resource. This allows the attacker to execute arbitrary code or commands in the context of the current user. If the user holds administrative rights, the attacker could take control of the affected system.

Conceptual Example Code

Below is a conceptual example of how an attacker might craft a malicious payload within an Excel file:

Sub Workbook_Open()
Shell("cmd.exe /c [malicious_command]", vbHide)
End Sub

In this example, the `Workbook_Open` subroutine runs when the Excel file is opened, executing the malicious command in the Windows command line via the `Shell` function.

Mitigation Guidance

Users are strongly recommended to immediately apply the vendor patch provided by Microsoft to remediate this vulnerability. As a temporary mitigation, users can also employ a Web Application Firewall (WAF) or Intrusion Detection System (IDS) to detect and potentially block attempts to exploit this vulnerability. However, these measures should not replace the need to apply the vendor patch, which provides a complete fix.

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Disclaimer:

The information and code presented in this article are provided for educational and defensive cybersecurity purposes only. Any conceptual or pseudocode examples are simplified representations intended to raise awareness and promote secure development and system configuration practices.

Do not use this information to attempt unauthorized access or exploit vulnerabilities on systems that you do not own or have explicit permission to test.

Ameeba and its authors do not endorse or condone malicious behavior and are not responsible for misuse of the content. Always follow ethical hacking guidelines, responsible disclosure practices, and local laws.
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