CVE-2012-1886 in Office Excel
Summary
by MITRE
Microsoft Excel 2003 SP3, 2007 SP2 and SP3, and 2010 SP1; Excel Viewer; and Office Compatibility Pack SP2 and SP3 allow remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted spreadsheet, aka "Excel Memory Corruption Vulnerability."
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Analysis
by VulDB Data Team • 04/19/2021
The CVE-2012-1886 vulnerability represents a critical memory corruption flaw affecting multiple versions of Microsoft Excel and related Office components. This vulnerability resides in the way these applications process certain spreadsheet files, specifically when handling malformed or crafted data structures within excel files. The flaw allows remote attackers to potentially execute arbitrary code on affected systems or cause denial of service conditions through carefully constructed malicious spreadsheets. The vulnerability impacts Microsoft Excel 2003 Service Pack 3, Excel 2007 Service Pack 2 and 3, Excel 2010 Service Pack 1, Excel Viewer, and the Office Compatibility Pack Service Pack 2 and 3. The technical nature of this vulnerability falls under the category of memory corruption, which is classified as CWE-125 in the Common Weakness Enumeration framework, representing an out-of-bounds read condition that can lead to arbitrary code execution.
The operational impact of this vulnerability extends beyond simple exploitation scenarios, as it represents a significant threat vector for attackers seeking to compromise office environments. The vulnerability can be triggered through various attack vectors including email attachments, web downloads, or file sharing scenarios where users open malicious Excel files. When exploited, the memory corruption can lead to complete system compromise, allowing attackers to execute malicious code with the privileges of the targeted user. This vulnerability particularly affects enterprise environments where Excel files are frequently shared and opened, making it a prime target for social engineering campaigns. The vulnerability also aligns with ATT&CK technique T1204.002 which involves executing malicious code through legitimate user interfaces, making it particularly dangerous in environments where users regularly open spreadsheet files from unknown sources.
The technical exploitation of CVE-2012-1886 typically involves crafting a malicious Excel file that contains malformed data structures designed to trigger the memory corruption during the parsing process. When the vulnerable application attempts to process these structures, it can overwrite memory locations or execute code from unexpected memory addresses. The vulnerability's exploitability is enhanced by the widespread use of Excel across organizations, making it relatively easy for attackers to find suitable targets. The memory corruption aspect of this vulnerability means that attackers can potentially bypass modern security protections like DEP and ASLR through techniques such as return-oriented programming or just-in-time compilation attacks. Organizations should note that this vulnerability requires no user interaction beyond opening the malicious file, making it particularly dangerous in targeted attack scenarios where attackers can leverage the element of surprise.
Mitigation strategies for CVE-2012-1886 should include immediate patching of affected systems through Microsoft's security updates, particularly the cumulative updates released in 2012. System administrators should implement strict file validation policies that prevent opening of Excel files from untrusted sources, including email attachments and unknown websites. Network segmentation and email filtering solutions should be configured to block potentially malicious Office files, especially those with extensions like .xls, .xlsx, or .xlsm. The implementation of application whitelisting policies can prevent unauthorized Excel applications from executing on systems, while regular security awareness training should educate users about the risks of opening unexpected spreadsheet files. Organizations should also consider implementing sandboxing solutions for processing untrusted Office files, as this can isolate potential exploitation attempts from the main system. The vulnerability's classification as a memory corruption issue makes it particularly important to maintain up-to-date antivirus signatures and endpoint protection solutions that can detect and block known malicious Excel file patterns. Additionally, the principle of least privilege should be enforced to limit the damage that could occur if exploitation were to succeed, ensuring that users have minimal necessary permissions to reduce potential impact.