CVE-2008-0112 in Excel
Summary
by MITRE
Unspecified vulnerability in Microsoft Excel 2000 SP3, and Office for Mac 2004 and 2008 allows user-assisted remote attackers to execute arbitrary code via a crafted .SLK file that is not properly handled when importing the file, aka "Excel File Import Vulnerability."
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Analysis
by VulDB Data Team • 08/06/2019
The vulnerability identified as CVE-2008-0112 represents a critical file import flaw in Microsoft Excel 2000 SP3 and Office for Mac 2004 and 2008 applications. This weakness manifests when the software processes specially crafted .SLK (Symbolic Link) files during the import operation, creating a potential attack vector for remote code execution. The vulnerability falls under the category of improper input validation and handling, which is classified as CWE-20 by the Common Weakness Enumeration framework. The attack requires user interaction to initiate the import process, making it a user-assisted remote attack rather than a fully autonomous exploit.
The technical flaw stems from the inadequate validation and parsing mechanisms within Excel's file import subsystem when encountering malformed .SLK files. These files contain a specific format that includes commands and data structures which, when improperly handled, can trigger memory corruption vulnerabilities. The vulnerability typically manifests through buffer overflows or stack corruption during the parsing of the .SLK file's internal structure, allowing attackers to inject and execute malicious code within the context of the running Excel process. This type of vulnerability aligns with ATT&CK technique T1203, which involves exploitation of software vulnerabilities for code execution.
The operational impact of this vulnerability extends beyond simple code execution, as it can lead to complete system compromise when attackers leverage additional attack vectors or chain this vulnerability with other exploits. The user-assisted nature of the attack means that victims must actively open or import the malicious file, but once initiated, the consequences can be severe including unauthorized access, data exfiltration, and persistence mechanisms. Organizations using these older versions of Microsoft Office face significant risk due to the lack of modern security features and the absence of security patches for these legacy products. The vulnerability affects environments where users might encounter .SLK files through email attachments, shared documents, or malicious websites, making it particularly dangerous in enterprise settings where document sharing is common.
Mitigation strategies for this vulnerability should focus on immediate remediation through software updates and patches, though support for these legacy versions may be limited. Organizations should implement strict file type restrictions and user education programs to prevent accidental execution of suspicious files. Network-based protections such as email filtering and web content filtering can help reduce the likelihood of users encountering malicious .SLK files. Additionally, implementing application whitelisting policies and restricting user privileges can limit the potential damage from successful exploitation attempts. The vulnerability serves as a reminder of the importance of maintaining current software versions and the risks associated with using outdated applications that no longer receive security updates, particularly in environments where security is paramount and threat landscapes continue to evolve.