CVE-2001-0852 in TUX HTTP Server
Summary
by MITRE
TUX HTTP server 2.1.0-2 in Red Hat Linux allows remote attackers to cause a denial of service via a long Host: header.
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Analysis
by VulDB Data Team • 09/29/2024
The vulnerability identified as CVE-2001-0852 affects the TUX HTTP server version 2.1.0-2 distributed with Red Hat Linux systems. This represents a classic denial of service weakness that exploits the server's handling of malformed HTTP headers. The TUX server, which was designed as a high-performance web server for Linux systems, fails to properly validate the length of the Host header field during HTTP request processing. This flaw allows remote attackers to craft malicious HTTP requests containing excessively long Host headers that can overwhelm the server's processing capabilities or trigger buffer overflow conditions.
The technical implementation of this vulnerability stems from insufficient input validation within the HTTP header parsing routine. When the TUX server receives an HTTP request with an abnormally long Host header, it attempts to process and store this data without adequate bounds checking. The server's memory management routines are not equipped to handle such oversized input fields, leading to potential buffer overflows or memory exhaustion conditions. This behavior aligns with CWE-122, which describes insufficient input validation leading to buffer overflows, and CWE-400, which covers resource exhaustion vulnerabilities. The vulnerability specifically manifests as a denial of service condition where legitimate service requests are disrupted due to the server's inability to process the malformed input properly.
From an operational impact perspective, this vulnerability presents a significant risk to web server availability and system reliability. Remote attackers can exploit this weakness to disrupt web services without requiring authentication or specialized access privileges, making it particularly dangerous in production environments. The denial of service effect can persist until the server is manually restarted or the vulnerable configuration is patched, potentially causing extended downtime for affected services. This vulnerability directly maps to ATT&CK technique T1499.004, which covers network denial of service attacks, and T1595.001, which involves reconnaissance techniques to identify vulnerable services. The impact extends beyond simple service disruption as it can affect business continuity and customer access to web applications hosted on affected systems.
Mitigation strategies for this vulnerability should prioritize immediate patching of the TUX server software to address the input validation flaw. System administrators should implement network-level protections such as rate limiting and header length restrictions to prevent exploitation attempts. Additionally, monitoring systems should be configured to detect unusual patterns in HTTP header sizes that may indicate attempted exploitation. The implementation of web application firewalls and intrusion prevention systems can provide additional layers of defense. Organizations should also consider implementing proper input sanitization measures and conducting regular security assessments to identify similar vulnerabilities in other server components. Long-term security improvements include adopting more robust server implementations with proper bounds checking and input validation mechanisms, aligning with security best practices outlined in NIST SP 800-53 and ISO 27001 standards for secure system development and operation.