CVE-2000-1147 in IIS
Summary
by MITRE
Buffer overflow in IIS ISAPI .ASP parsing mechanism allows attackers to execute arbitrary commands via a long string to the "LANGUAGE" argument in a script tag.
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Analysis
by VulDB Data Team • 10/11/2025
The vulnerability identified as CVE-2000-1147 represents a critical buffer overflow flaw within the Internet Information Services (IIS) ISAPI extension responsible for parsing ASP scripts. This vulnerability specifically targets the handling of the "LANGUAGE" attribute within script tags, creating an exploitable condition that can be leveraged by malicious actors to execute arbitrary code on affected systems. The flaw exists in the way IIS processes and validates input parameters when parsing ASP files through its ISAPI interface, which serves as a bridge between the web server and the scripting engine.
The technical implementation of this vulnerability stems from inadequate input validation and buffer management within the ISAPI extension component of IIS version 5.0 and earlier. When a web server receives an ASP request containing a script tag with an excessively long string in the LANGUAGE argument, the parsing mechanism fails to properly bounds-check the input data. This results in memory corruption where the buffer overflow occurs in the stack memory region allocated for processing the script tag parameters. The overflow can overwrite adjacent memory locations including return addresses and control data, enabling attackers to redirect program execution flow and inject malicious code that executes with the privileges of the IIS service account.
From an operational perspective, this vulnerability poses significant risks to web server security as it allows remote code execution without authentication requirements. Attackers can craft malicious ASP pages containing overly long LANGUAGE arguments that trigger the buffer overflow condition when processed by the IIS server. The impact extends beyond simple code execution to potential system compromise, as the vulnerable IIS service typically runs with elevated privileges. This vulnerability directly aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a classic example of unsafe string handling in server-side web applications. The attack vector is particularly dangerous because it can be exploited through standard HTTP requests without requiring any special authentication or privileged access.
The exploitation of CVE-2000-1147 can be mapped to several tactics within the MITRE ATT&CK framework, specifically encompassing the execution and privilege escalation categories. The vulnerability enables initial access through remote code execution capabilities, which can be classified under ATT&CK technique T1059 for command and script interpreter execution. Additionally, the ability to execute arbitrary code with system-level privileges aligns with ATT&CK technique T1068 for local privilege escalation. Organizations affected by this vulnerability face potential data breaches, system compromise, and complete loss of web server control. The vulnerability's widespread impact on IIS 5.0 and earlier versions made it a prime target for automated exploitation tools and malware campaigns during the early 2000s. Mitigation strategies should include immediate patching of IIS installations, implementing proper input validation measures, and deploying network segmentation controls to limit the potential impact of successful exploitation attempts. System administrators should also consider implementing web application firewalls and monitoring for suspicious script tag patterns that could indicate exploitation attempts.