CVE-2008-3003 in Office
Summary
by MITRE
Microsoft Office Excel 2007 Gold and SP1 does not properly delete the PWD (password) string from connections.xml when a .xlsx file is configured not to save the remote data session password, which allows local users to obtain sensitive information and obtain access to a remote data source, aka the "Excel Credential Caching Vulnerability."
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Analysis
by VulDB Data Team • 08/15/2019
The CVE-2008-3003 vulnerability represents a critical information disclosure flaw in Microsoft Office Excel 2007 that stems from improper handling of credential storage mechanisms within spreadsheet files. This vulnerability specifically affects Excel 2007 Gold and Service Pack 1 versions, where the application fails to adequately purge password strings from the connections.xml file even when users explicitly configure files to not save remote data session passwords. The flaw exists in the application's credential management system and directly violates security principles related to proper credential handling and sensitive data protection.
The technical implementation of this vulnerability occurs within Excel's data connection management subsystem where remote data sources are configured through the connections.xml file structure. When users establish connections to external data sources such as databases, web services, or other remote systems, Excel stores connection parameters including credentials within this XML file. The vulnerability manifests when users select options to not save passwords, yet the application continues to retain the password string in memory or in the file structure, creating a persistent credential cache that remains accessible to local users. This behavior directly maps to CWE-200 (Information Exposure) and CWE-522 (Insufficiently Protected Credentials) categories, as it exposes sensitive authentication information to unauthorized local access.
The operational impact of this vulnerability extends beyond simple information disclosure to enable potential unauthorized access to remote data sources. Local attackers who gain access to the affected Excel files can extract cached passwords from the connections.xml file, potentially allowing them to access the same remote data sources that the original user had access to. This creates a privilege escalation scenario where local users can leverage the cached credentials to gain access to corporate databases, web services, or other sensitive systems. The vulnerability particularly affects enterprise environments where Excel files may contain connections to critical systems, and where local users might have legitimate access to the file system but should not have access to the underlying data sources. This scenario aligns with ATT&CK technique T1555.003 (Credentials from Password Stores) and T1078 (Valid Accounts) as it exploits legitimate credential storage mechanisms to gain unauthorized access.
Mitigation strategies for CVE-2008-3003 should focus on both immediate remediation and long-term security hardening. Microsoft released patches and updates that address the credential caching behavior in subsequent versions of Excel, and organizations should ensure all systems are updated to the latest security patches. Additionally, administrators should implement strict file access controls and consider disabling external data connections in Excel files when possible. The vulnerability highlights the importance of proper credential management practices and the need for applications to implement secure credential handling mechanisms that fully respect user configuration choices regarding credential persistence. Organizations should also consider implementing data loss prevention solutions that monitor for sensitive information exposure within office documents and establish policies that restrict the use of external data connections in sensitive environments.