CVE-2003-0349 in Windows
Summary
by MITRE
Buffer overflow in the streaming media component for logging multicast requests in the ISAPI for the logging capability of Microsoft Windows Media Services (nsiislog.dll), as installed in IIS 5.0, allows remote attackers to execute arbitrary code via a large POST request to nsiislog.dll.
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Analysis
by VulDB Data Team • 08/18/2025
The vulnerability described in CVE-2003-0349 represents a critical buffer overflow condition within the Microsoft Windows Media Services streaming media component that specifically affects the ISAPI logging functionality. This flaw exists in the nsiislog.dll module which is installed as part of Windows Media Services when configured to work with Internet Information Services 5.0. The vulnerability manifests when the system processes multicast requests through the logging capability, creating an exploitable condition that can be leveraged by remote attackers to gain unauthorized code execution privileges.
The technical nature of this vulnerability stems from inadequate input validation within the nsiislog.dll component that handles logging of multicast requests. When a remote attacker submits a specially crafted POST request containing an excessive amount of data to the affected nsiislog.dll module, the system fails to properly bounds-check the incoming data before copying it into a fixed-size buffer. This classic buffer overflow condition occurs because the application does not verify that the incoming data length matches the allocated buffer space, allowing an attacker to overwrite adjacent memory locations with malicious code or manipulate program execution flow.
The operational impact of this vulnerability extends beyond simple remote code execution, as it provides attackers with the ability to completely compromise the affected system. Since the vulnerability affects the ISAPI logging component that operates within the IIS 5.0 environment, successful exploitation could result in full system compromise, allowing attackers to execute arbitrary commands with the privileges of the IIS service account. This presents a significant risk to organizations relying on Windows Media Services integrated with IIS 5.0, as the compromised system could serve as a foothold for further network infiltration or be used to establish persistent access.
The vulnerability aligns with CWE-121, which describes the classic stack-based buffer overflow condition, and represents a common pattern of memory safety issues that have historically plagued Windows-based systems. From an ATT&CK framework perspective, this vulnerability maps to the T1059.007 technique for command and scripting interpreter, specifically through the use of the Windows command shell, as well as T1078.002 for valid accounts and T1105 for remote access tools. Organizations should note that this vulnerability was present in Windows Media Services versions that were widely deployed in enterprise environments during the early 2000s, making it particularly dangerous for legacy systems that may not have received proper security updates. The exploitability of this condition requires network access to the affected IIS server and knowledge of the specific logging endpoint, but the potential impact makes it a high-priority target for remediation in any environment still running vulnerable configurations.