CVE-2002-1138 in SQL Server
Summary
by MITRE
Microsoft SQL Server 7.0 and 2000, including Microsoft Data Engine (MSDE) 1.0 and Microsoft Desktop Engine (MSDE) 2000, writes output files for scheduled jobs under its own privileges instead of the entity that launched it, which allows attackers to overwrite system files, aka "Flaw in Output File Handling for Scheduled Jobs."
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Analysis
by VulDB Data Team • 09/08/2025
This vulnerability exists in Microsoft SQL Server versions 7.0 and 2000, including the associated Microsoft Data Engine and Desktop Engine implementations. The core issue stems from how the system handles output file creation for scheduled jobs within the SQL Server Agent service. When SQL Server executes scheduled jobs, it creates output files using its own security context rather than inheriting the privileges of the user who initiated the job execution. This design flaw creates a significant privilege escalation vector that can be exploited by malicious actors.
The technical implementation of this vulnerability allows attackers to manipulate the file system through the scheduled job mechanism. Since SQL Server runs with elevated privileges and creates output files under its own account, an attacker who can schedule jobs or modify existing job configurations can direct these jobs to write output to critical system locations. This behavior directly violates the principle of least privilege and creates opportunities for arbitrary file overwrites, particularly targeting system directories or files with sensitive permissions. The vulnerability is categorized under CWE-276 as improper file permissions and falls within the ATT&CK framework's privilege escalation techniques.
The operational impact of this vulnerability extends beyond simple file overwrites to potentially enable complete system compromise. Attackers can leverage this flaw to overwrite critical system executables, configuration files, or registry entries that would normally require administrative privileges to modify. This capability can lead to persistent backdoors, system instability, or complete system takeover. The vulnerability affects not just the database server itself but also any system where SQL Server is installed, making it particularly dangerous in enterprise environments where database servers often run with elevated privileges.
Mitigation strategies for this vulnerability include immediate application of Microsoft security patches, which address the core file handling behavior in SQL Server Agent. Administrators should also implement strict access controls to SQL Server Agent job configurations and limit the number of users who can create or modify scheduled jobs. Network segmentation and privilege separation can reduce the attack surface, while regular monitoring of file system changes can help detect exploitation attempts. Additionally, implementing proper file system permissions and using least privilege principles for SQL Server service accounts can significantly reduce the potential impact of this vulnerability. Organizations should also consider implementing application whitelisting policies to prevent unauthorized executable modifications.