CVE-2012-0143 in Excel
Summary
by MITRE
Microsoft Excel 2003 SP3 and Office 2008 for Mac do not properly handle memory during the opening of files, which allows remote attackers to execute arbitrary code via a crafted spreadsheet, aka "Excel Memory Corruption Using Various Modified Bytes Vulnerability."
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 03/24/2021
The vulnerability identified as CVE-2012-0143 represents a critical memory corruption flaw affecting Microsoft Excel 2003 SP3 and Office 2008 for Mac applications. This vulnerability stems from improper memory handling during the file opening process, creating a pathway for remote attackers to execute arbitrary code on affected systems. The flaw manifests when these applications process specially crafted spreadsheet files that contain modified bytes designed to exploit memory management weaknesses within the Excel application.
The technical nature of this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions where programs access memory locations beyond allocated boundaries. The flaw occurs during the parsing of spreadsheet files where Excel fails to properly validate or sanitize input data, leading to memory corruption that can be leveraged by attackers. The vulnerability is particularly dangerous because it can be triggered remotely through malicious spreadsheet files delivered via email attachments, web downloads, or shared network locations, making it an attractive target for phishing campaigns and targeted attacks.
From an operational impact perspective, this vulnerability presents significant risks to organizations relying on these older versions of Microsoft Office. The ability to execute arbitrary code remotely means attackers can gain full system control, potentially leading to data exfiltration, system compromise, or deployment of additional malicious software. The vulnerability affects users who may not be aware of the security risk, as the malicious file appears legitimate and can be easily delivered through normal business communication channels. This makes the attack surface particularly broad and difficult to control without proper security measures.
The exploitation of this vulnerability typically follows an attacker's strategy aligned with ATT&CK technique T1203, which involves gaining access through malicious files. The attack chain begins with the delivery of a crafted spreadsheet file, followed by user interaction to open the file, which triggers the memory corruption and code execution. Organizations should implement multiple layers of defense including email filtering, application whitelisting, and regular security updates to mitigate this risk. The vulnerability also highlights the importance of keeping legacy software updated, as Microsoft has since released patches and updates to address similar memory corruption issues in newer versions of Office.
Security professionals should prioritize the immediate remediation of affected systems through patch management processes, as the vulnerability represents a persistent threat that can be exploited without user interaction once a malicious file is opened. The memory corruption aspect of this vulnerability makes it particularly challenging to detect through traditional signature-based methods, requiring behavioral analysis and advanced threat detection capabilities. Organizations should also consider implementing network segmentation and access controls to limit the potential impact of successful exploitation, as the vulnerability can lead to complete system compromise and lateral movement within networks.