CVE-2022-30173 in Excel
Summary
by MITRE • 06/16/2022
Microsoft Excel Remote Code Execution Vulnerability.
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Analysis
by VulDB Data Team • 06/17/2022
The CVE-2022-30173 vulnerability represents a critical remote code execution flaw discovered in Microsoft Excel software, specifically affecting versions of the application that process certain file formats. This vulnerability stems from improper input validation within Excel's handling of maliciously crafted spreadsheet files, creating a pathway for attackers to execute arbitrary code on targeted systems. The flaw exists in the way Excel parses specific elements within workbook files, particularly when dealing with complex formula structures and embedded objects that trigger unexpected behavior in the application's memory management systems.
The technical implementation of this vulnerability involves a memory corruption issue that occurs when Excel attempts to process malformed or specially crafted cells within spreadsheet documents. Attackers can exploit this by creating malicious .xlsx files containing carefully constructed formulas or object references that cause Excel to allocate memory improperly, leading to buffer overflows or other memory corruption conditions. The vulnerability is particularly dangerous because it can be triggered through normal file opening operations, making it difficult for users to distinguish between legitimate and malicious files. This type of flaw typically maps to CWE-121, which describes stack-based buffer overflow conditions, and may also exhibit characteristics of CWE-787, representing out-of-bounds write vulnerabilities.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with the ability to fully compromise affected systems without requiring user interaction beyond opening a malicious file. Once executed, the remote code can establish persistence mechanisms, escalate privileges, and potentially spread laterally within network environments. The vulnerability's exploitation aligns with ATT&CK technique T1059, which covers command and scripting interpreter usage, and may also involve T1078 for legitimate credentials use and T1566 for social engineering tactics. Organizations running affected Excel versions face significant risk of data breaches, system compromise, and potential full network infiltration through this single point of entry.
Mitigation strategies for CVE-2022-30173 should prioritize immediate patch deployment from Microsoft, as the company released security updates addressing this specific vulnerability. Organizations should also implement strict file validation policies, particularly for incoming spreadsheet files, and consider deploying application control solutions that restrict Excel's ability to process untrusted files. Network segmentation and monitoring solutions should be enhanced to detect unusual Excel process behaviors or attempts to download and execute malicious content. Additionally, user education programs should emphasize the importance of verifying file sources and avoiding opening suspicious spreadsheet attachments. Security teams should monitor for indicators of compromise related to this vulnerability and maintain updated threat intelligence feeds to identify potential exploitation attempts in their environments.