CVE-2011-0026 in Windows
Summary
by MITRE
Integer signedness error in the SQLConnectW function in an ODBC API (odbc32.dll) in Microsoft Data Access Components (MDAC) 2.8 SP1 and SP2, and Windows Data Access Components (WDAC) 6.0, allows remote attackers to execute arbitrary code via a long string in the Data Source Name (DSN) and a crafted szDSN argument, which bypasses a signed comparison and leads to a buffer overflow, aka "DSN Overflow Vulnerability."
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Analysis
by VulDB Data Team • 01/26/2025
The CVE-2011-0026 vulnerability represents a critical integer signedness error within the SQLConnectW function of Microsoft's Data Access Components, specifically affecting odbc32.dll in MDAC 2.8 SP1 and SP2 as well as WDAC 6.0. This flaw manifests as a buffer overflow condition that can be exploited remotely to execute arbitrary code on affected systems. The vulnerability stems from improper handling of string length comparisons where signed integer variables are used in contexts that should employ unsigned comparisons, creating a scenario where malicious input can bypass validation mechanisms.
The technical exploitation of this vulnerability occurs through a carefully crafted Data Source Name (DSN) parameter that contains an excessively long string. When the SQLConnectW function processes this malformed DSN, the signed comparison logic fails to properly validate the string length, allowing an attacker to manipulate the buffer boundaries. This manipulation results in a buffer overflow condition where the oversized string overwrites adjacent memory locations, potentially enabling code execution. The vulnerability is particularly dangerous because it operates at the API level and can be triggered through various attack vectors including network-based exploitation.
From an operational impact perspective, this vulnerability affects systems running vulnerable versions of Microsoft Data Access Components, which were widely deployed across enterprise environments for database connectivity. The remote code execution capability means that attackers could potentially compromise entire systems without requiring local access or user interaction. The vulnerability affects both client and server environments where ODBC connections are established, making it a significant concern for database administrators and security teams responsible for protecting enterprise data infrastructure. Organizations using legacy systems or those that have not updated their MDAC components remain particularly vulnerable to this attack vector.
Mitigation strategies for CVE-2011-0026 should prioritize immediate patching of affected systems with Microsoft security updates, as this vulnerability has been addressed through official Microsoft security bulletins. Network segmentation and firewall rules should be implemented to restrict access to ODBC endpoints and limit potential attack surfaces. Input validation mechanisms should be strengthened at application level to prevent malformed DSN strings from reaching the vulnerable API functions. Additionally, monitoring systems should be configured to detect unusual patterns in database connection attempts and DSN parameter usage. This vulnerability aligns with CWE-190, Integer Overflow or Wraparound, and maps to ATT&CK technique T1059.007 for command and script interpreter execution, highlighting the need for comprehensive defensive measures including application whitelisting and runtime protection mechanisms. Organizations should also consider implementing intrusion detection systems that can identify exploitation attempts targeting this specific buffer overflow condition.