CVE-2008-4110 in SQL Server
Summary
by MITRE
Buffer overflow in the SQLVDIRLib.SQLVDirControl ActiveX control in Tools\Binn\sqlvdir.dll in Microsoft SQL Server 2000 (aka SQL Server 8.0) allows remote attackers to cause a denial of service (browser crash) or possibly execute arbitrary code via a long URL in the second argument to the Connect method. NOTE: this issue is not a vulnerability in many environments, since the control is not marked as safe for scripting and would not execute with default Internet Explorer settings.
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Analysis
by VulDB Data Team • 02/12/2017
The vulnerability described in CVE-2008-4110 represents a critical buffer overflow flaw within Microsoft SQL Server 2000's SQLVDIRLib.SQLVDirControl ActiveX component. This particular vulnerability exists in the sqlvdir.dll file located within the Tools\Binn directory of the SQL Server installation, making it accessible through the web-based interface of the database management system. The flaw specifically manifests when processing the Connect method of the ActiveX control, where the second argument accepts URL parameters that are not properly validated for length, creating a condition where malicious input can exceed the allocated buffer space. The vulnerability operates at the application layer and can be exploited through web-based attack vectors, particularly targeting the ActiveX control execution environment within Internet Explorer browsers.
The technical implementation of this buffer overflow vulnerability stems from inadequate input validation within the SQLVDIRLib.SQLVDirControl ActiveX component. When the Connect method processes URL arguments, the control fails to enforce proper bounds checking on the input parameters, allowing an attacker to supply excessively long URL strings that exceed the predetermined buffer limits. This condition creates a classic stack-based buffer overflow scenario where the excess data overwrites adjacent memory locations, potentially corrupting program execution flow. The vulnerability specifically targets the second parameter of the Connect method, which is expected to contain a URL string but can be manipulated to contain malicious data exceeding normal parameter length constraints. This flaw falls under the Common Weakness Enumeration category of CWE-121, which describes stack-based buffer overflow conditions that occur when insufficient bounds checking is performed on buffer operations.
The operational impact of CVE-2008-4110 extends beyond simple denial of service conditions to potentially enable remote code execution within the context of the vulnerable application. While the vulnerability may not be exploitable in all environments due to default Internet Explorer security settings, it poses significant risks when ActiveX controls are enabled and the control is marked as safe for scripting. The potential for remote code execution arises from the ability to overwrite critical memory locations and potentially redirect program execution flow through controlled input manipulation. Attackers can leverage this vulnerability to crash browser applications, cause system instability, or in more sophisticated exploitation scenarios, gain unauthorized access to systems running vulnerable SQL Server installations. The impact is particularly concerning in enterprise environments where SQL Server components may be exposed to untrusted network traffic and where ActiveX controls are enabled for legitimate business purposes.
The mitigation strategies for this vulnerability focus primarily on disabling or restricting ActiveX control execution, particularly in environments where the control is not essential for legitimate operations. Microsoft's recommended approach involves ensuring that the SQLVDIRLib.SQLVDirControl is not marked as safe for scripting and implementing proper security configurations within Internet Explorer to prevent automatic execution of potentially dangerous ActiveX components. Organizations should also consider implementing network segmentation and access controls to limit exposure of SQL Server components to untrusted users. Additionally, the vulnerability demonstrates the importance of proper input validation and bounds checking in application development, particularly for components that handle external input through web interfaces. Security professionals should also implement regular vulnerability assessments and maintain updated security patches to prevent exploitation of known vulnerabilities in legacy systems. The vulnerability aligns with ATT&CK technique T1190 which describes the exploitation of vulnerabilities in software components, particularly those involving buffer overflows and memory corruption.