CVE-2000-1087 in SQL Server
Summary
by MITRE
The xp_proxiedmetadata function in Microsoft SQL Server 2000 and SQL Server Desktop Engine (MSDE) does not properly restrict the length of a buffer before calling the srv_paraminfo function in the SQL Server API for Extended Stored Procedures (XP), which allows an attacker to cause a denial of service or execute arbitrary commands, aka the "Extended Stored Procedure Parameter Parsing" vulnerability.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 04/24/2017
The xp_proxiedmetadata function in Microsoft SQL Server 2000 and SQL Server Desktop Engine represents a critical buffer overflow vulnerability that stems from improper input validation within the extended stored procedure API framework. This flaw exists in the SQL Server API for Extended Stored Procedures where the srv_paraminfo function is invoked without adequate buffer length restrictions, creating a pathway for malicious input to overwrite memory segments. The vulnerability specifically targets the parameter parsing mechanism that handles extended procedure calls, making it particularly dangerous as it operates within the core database execution environment where privilege escalation and code execution opportunities are abundant. The issue manifests when the xp_proxiedmetadata function processes user-supplied parameters that exceed predetermined buffer limits, leading to potential memory corruption and system instability.
The technical exploitation of this vulnerability follows a classic buffer overflow pattern that aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. When an attacker crafts malicious input parameters that exceed the expected buffer size, the srv_paraminfo function call fails to validate the input length properly, resulting in memory corruption that can be leveraged for arbitrary code execution. The vulnerability operates at the API level within SQL Server's extended procedure framework, making it particularly challenging to detect and prevent through standard network-based security measures. This flaw essentially allows an attacker to manipulate the execution flow of the database server by overwriting critical memory segments, potentially leading to complete system compromise.
The operational impact of CVE-2000-1087 extends beyond simple denial of service scenarios to encompass full system compromise capabilities that align with ATT&CK technique T1059.002 for command and scripting interpreter. An attacker who successfully exploits this vulnerability can execute arbitrary commands with the privileges of the SQL Server service account, which typically runs with elevated system permissions. The denial of service aspect of this vulnerability can cause database server crashes, application downtime, and service interruptions that directly impact business operations. More critically, the arbitrary code execution capability means that attackers can potentially establish persistent backdoors, escalate privileges, or exfiltrate sensitive data from the database environment. The vulnerability affects both SQL Server 2000 and MSDE installations, representing a broad attack surface that includes both enterprise and desktop database deployments.
Mitigation strategies for this vulnerability must address both immediate patching requirements and defensive measures within the database environment. Microsoft released security updates for SQL Server 2000 and MSDE that correct the buffer length validation issues in the xp_proxiedmetadata function, requiring administrators to apply these patches immediately. Network segmentation and access control measures should limit exposure by restricting direct database access to trusted network segments and implementing proper authentication controls. Database administrators should disable unnecessary extended stored procedures through the xp_cmdshell and similar functions, as these provide additional attack vectors that compound the risks associated with this vulnerability. Monitoring for suspicious parameter values and implementing application-level input validation can help detect attempts to exploit this flaw before successful compromise occurs, while also providing valuable intelligence for incident response activities. The vulnerability demonstrates the critical importance of proper input validation in database API implementations and serves as a reminder of the security implications when privilege escalation opportunities exist within database server environments.