CVE-2000-1088 in SQL Server
Summary
by MITRE
The xp_SetSQLSecurity 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.
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Analysis
by VulDB Data Team • 04/24/2017
The CVE-2000-1088 vulnerability represents a critical buffer overflow flaw within Microsoft SQL Server 2000 and SQL Server Desktop Engine implementations that stems from improper input validation in the xp_SetSQLSecurity extended stored procedure. This vulnerability operates at the intersection of buffer management and privilege escalation within database server environments, creating a pathway for malicious actors to compromise system integrity. The flaw specifically manifests when the xp_SetSQLSecurity function processes parameter inputs without adequate length restrictions before invoking the srv_paraminfo API function, establishing a classic buffer overrun condition that can be exploited by attackers to manipulate memory structures.
The technical exploitation of this vulnerability leverages the inherent weakness in parameter parsing mechanisms within SQL Server's extended stored procedure framework. When an attacker supplies an overly long parameter string to the xp_SetSQLSecurity function, the system fails to validate the input length against predetermined buffer boundaries before passing the data to the srv_paraminfo function. This omission creates a memory corruption scenario where the excessive input overflows the allocated buffer space, potentially allowing attackers to overwrite adjacent memory locations or manipulate function pointers. The vulnerability aligns with CWE-121, which categorizes buffer overflow conditions, and demonstrates how improper bounds checking in API parameter handling can create exploitable conditions. The attack surface extends beyond simple memory corruption to include potential privilege escalation opportunities, as the extended stored procedures operate with elevated privileges within the database environment.
The operational impact of CVE-2000-1088 encompasses both denial of service and arbitrary code execution capabilities, making it particularly dangerous for database server environments. In a denial of service scenario, attackers can cause SQL Server processes to crash or become unresponsive through controlled buffer overflows, disrupting database operations and potentially affecting business continuity. More critically, the vulnerability enables arbitrary command execution when attackers can manipulate the memory layout to redirect program execution flow, effectively allowing them to run malicious code with the privileges of the SQL Server service account. This capability directly maps to ATT&CK technique T1059, which describes the execution of commands through various system interfaces, and T1078, which addresses legitimate credentials use for persistence and privilege escalation. The vulnerability's exploitation can result in complete system compromise when the SQL Server service operates with administrative privileges.
Mitigation strategies for this vulnerability require immediate patch application from Microsoft, as the company released specific updates to address the buffer overflow condition in affected SQL Server versions. Organizations should implement network segmentation to limit access to SQL Server instances and employ principle of least privilege when configuring database service accounts to minimize potential damage from successful exploitation. Input validation controls should be implemented at multiple layers including application firewalls and database access controls to prevent malformed parameter inputs from reaching vulnerable extended stored procedures. Additionally, monitoring systems should be configured to detect unusual parameter lengths or patterns that might indicate exploitation attempts. The vulnerability serves as a historical example of how API parameter handling flaws can create persistent security risks, emphasizing the importance of proper buffer management and input validation in database server implementations. Regular security assessments and vulnerability scanning should be conducted to identify similar conditions in other extended stored procedures or API functions that might present analogous risks to system security.