CVE-2002-1023 in BadBlue
Summary
by MITRE
BadBlue server allows remote attackers to cause a denial of service (crash) via an HTTP GET request without a URI.
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Analysis
by VulDB Data Team • 09/10/2025
The vulnerability identified as CVE-2002-1023 affects the BadBlue web server implementation, representing a classic denial of service flaw that exploits improper handling of malformed HTTP requests. This vulnerability specifically targets the server's response mechanism when processing HTTP GET requests that lack a URI component, creating a condition where the server fails to properly validate incoming request parameters before attempting to process them. The flaw demonstrates a fundamental weakness in input validation and request parsing logic within the web server software.
This technical weakness manifests as a buffer over-read or improper state handling when the server encounters an HTTP GET request devoid of a URI specification. The BadBlue server, like many web servers of its era, does not adequately sanitize or validate the structure of incoming HTTP requests before attempting to parse and process them. When a malformed request lacking a URI is received, the server's internal processing routines fail to handle this edge case gracefully, leading to a crash or complete service interruption. This behavior aligns with CWE-122, which describes buffer overflow conditions, and CWE-20, which covers improper input validation scenarios.
The operational impact of this vulnerability extends beyond simple service disruption, as it represents a critical weakness that could be exploited by malicious actors to systematically disable web services. Attackers can leverage this flaw by simply sending a crafted HTTP GET request without specifying a URI, causing the BadBlue server to crash and become unavailable to legitimate users. This type of attack falls under the ATT&CK technique T1499.004, which describes network denial of service attacks targeting web services. The vulnerability is particularly concerning because it requires minimal effort to exploit and can be automated, making it attractive to threat actors seeking to disrupt web-based operations.
The root cause of this vulnerability lies in the server's insufficient error handling and input validation mechanisms. Modern web server implementations typically include robust request parsing routines that can gracefully handle malformed requests or provide appropriate HTTP error responses when encountering invalid input. The BadBlue server's failure to implement such safeguards demonstrates a lack of proper defensive programming practices that were becoming standard in the early 2000s. This vulnerability also highlights the importance of adhering to secure coding practices as outlined in the OWASP Secure Coding Practices, which emphasize the need for comprehensive input validation and error handling in web applications.
Organizations affected by this vulnerability should implement immediate mitigations including deploying patched versions of the BadBlue server software, implementing network-level filtering to block malformed HTTP requests, and configuring intrusion detection systems to monitor for exploitation attempts. The recommended approach involves applying vendor-specific patches that enhance input validation and error handling capabilities within the server's request processing pipeline. Additionally, network administrators should consider implementing rate limiting and request validation mechanisms at the network perimeter to prevent exploitation attempts. This vulnerability underscores the critical importance of maintaining up-to-date security patches and implementing defense-in-depth strategies to protect against known vulnerabilities that could compromise service availability.