CVE-2002-0150 in IIS
Summary
by MITRE
Buffer overflow in Internet Information Server (IIS) 4.0, 5.0, and 5.1 allows remote attackers to spoof the safety check for HTTP headers and cause a denial of service or execute arbitrary code via HTTP header field values.
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Analysis
by VulDB Data Team • 09/22/2025
The vulnerability described in CVE-2002-0150 represents a critical buffer overflow flaw affecting Microsoft Internet Information Server versions 4.0, 5.0, and 5.1. This vulnerability resides in the HTTP header processing mechanism of IIS, where improper validation of header field values leads to memory corruption. The flaw occurs when the web server attempts to process HTTP headers that exceed predetermined buffer limits, creating a condition where attacker-controlled data can overwrite adjacent memory locations. The vulnerability is particularly dangerous because it can be exploited remotely without authentication, making it accessible to any attacker with network connectivity to the affected server. According to CWE-121, this represents a classic stack-based buffer overflow condition where insufficient bounds checking allows arbitrary data to overwrite stack memory, potentially leading to code execution or system compromise.
The technical exploitation of this vulnerability involves crafting malicious HTTP header values that exceed the allocated buffer space, typically through carefully constructed header field names or values that trigger memory corruption during parsing operations. When IIS processes these malformed headers, the buffer overflow can overwrite return addresses, function pointers, or other critical memory structures, enabling attackers to redirect execution flow or inject malicious code. The vulnerability's impact extends beyond simple denial of service, as successful exploitation can result in complete system compromise, allowing attackers to execute arbitrary code with the privileges of the IIS service account. This aligns with ATT&CK technique T1203, which describes the use of buffer overflow exploits to gain code execution capabilities, and T1499, which covers network denial of service attacks that can be achieved through such memory corruption vulnerabilities.
The operational impact of CVE-2002-0150 is severe for organizations running affected IIS versions, as the vulnerability can be leveraged for both persistent attacks and immediate service disruption. Attackers can use this vulnerability to establish persistent access to compromised systems, deploy backdoors, or escalate privileges within the network. The remote nature of the exploit means that attackers can target vulnerable servers from anywhere on the internet without requiring physical access or prior authentication. Organizations running these legacy IIS versions face significant risk exposure, as the vulnerability has been widely documented and actively exploited in the wild. The flaw also creates cascading effects where a single compromised IIS server can serve as a foothold for broader network infiltration, particularly in environments where IIS serves as a primary web application platform. Given the age of these IIS versions, many organizations may still be running vulnerable configurations, making this attack vector particularly relevant for legacy system security assessments.
Mitigation strategies for this vulnerability require immediate action including deployment of Microsoft security patches, which address the buffer overflow through proper input validation and memory management. Organizations should implement network segmentation to isolate vulnerable IIS servers from critical network segments, and establish robust monitoring for unusual HTTP header patterns that might indicate exploitation attempts. The implementation of web application firewalls and intrusion detection systems can provide additional layers of protection by detecting and blocking malicious header values before they reach the vulnerable IIS service. Regular security audits should verify that all IIS installations have been properly patched and that no legacy versions remain operational. System administrators must also consider implementing strict HTTP header validation policies and monitoring for anomalous behavior in web server logs that could indicate exploitation attempts. The vulnerability underscores the importance of maintaining up-to-date security patches and demonstrates how legacy software systems can remain vulnerable to well-known exploits for extended periods when proper maintenance practices are not followed.