CVE-2003-0507 in Windows
Summary
by MITRE
Stack-based buffer overflow in Active Directory in Windows 2000 before SP4 allows remote attackers to cause a denial of service (reboot) and possibly execute arbitrary code via an LDAP version 3 search request with a large number of (1) "AND," (2) "OR," and possibly other statements, which causes LSASS.EXE to crash.
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Analysis
by VulDB Data Team • 08/13/2025
The vulnerability described in CVE-2003-0507 represents a critical stack-based buffer overflow within the Active Directory service of Windows 2000 systems prior to Service Pack 4. This flaw exists within the Lightweight Directory Access Protocol (LDAP) implementation that handles directory queries, specifically affecting the Local Security Authority Subsystem Service (LSASS.EXE) process responsible for authentication and security policy enforcement. The vulnerability arises from insufficient input validation when processing complex LDAP search requests that contain an excessive number of logical operators.
The technical implementation of this vulnerability stems from improper bounds checking within the LDAP parsing logic of Active Directory. When an LDAP version 3 search request contains a large number of concatenated "AND" and "OR" logical operators, the system fails to properly validate the stack memory allocation required for processing these operations. This results in a classic stack buffer overflow condition where maliciously crafted search requests can overwrite adjacent memory locations, potentially corrupting the execution flow of LSASS.EXE. The vulnerability specifically targets the parsing of complex search filters that exceed the allocated stack buffer space, causing the service to crash and restart.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enabling remote code execution in certain scenarios. When LSASS.EXE crashes due to the buffer overflow, the system experiences a reboot, disrupting authentication services and potentially affecting other security-critical functions. The remote exploitation capability means that attackers can leverage this vulnerability from outside the network perimeter without requiring prior authentication credentials. This makes the vulnerability particularly dangerous for enterprise environments where Active Directory services are exposed to external traffic, as it can be exploited to gain unauthorized access to authentication infrastructure and potentially escalate privileges within the domain.
Organizations affected by this vulnerability should implement immediate mitigations including applying Microsoft Security Bulletin MS03-030 which provides the necessary patches for Windows 2000 systems. Network segmentation and firewall rules should be implemented to restrict LDAP traffic to trusted sources only, limiting exposure to external attackers. The vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which specifically addresses buffer overflows occurring in stack memory regions. From an attacker perspective, this vulnerability maps to ATT&CK technique T1078 Valid Accounts for maintaining persistence and T1489 Service Stop for denial of service operations, while potentially enabling T1059 Command and Scripting Interpreter for executing malicious code.
The broader implications of this vulnerability highlight the importance of proper input validation and memory management in security-critical services. Active Directory's exposure to LDAP traffic makes it a prime target for attackers seeking to compromise authentication infrastructure, as successful exploitation can provide access to user credentials, group memberships, and other sensitive directory information. Organizations should also consider implementing intrusion detection systems to monitor for suspicious LDAP search patterns that might indicate exploitation attempts, particularly searches containing unusually large numbers of logical operators. Regular security assessments and vulnerability scanning should be conducted to identify unpatched systems, as this vulnerability represents a legacy issue that could still affect older systems that have not received proper security updates.