CVE-2001-0252 in iPlanet Enterprise Server
Summary
by MITRE
iPlanet (formerly Netscape) Enterprise Server 4.1 allows remote attackers to cause a denial of service via a long HTTP GET request that contains many "/../" (dot dot) sequences.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 10/07/2025
The vulnerability identified as CVE-2001-0252 affects the iPlanet Enterprise Server version 4.1, formerly known as Netscape Enterprise Server, presenting a significant denial of service threat to web applications. This vulnerability stems from the server's inadequate handling of malformed HTTP GET requests containing excessive directory traversal sequences, specifically multiple instances of "/../" patterns that attempt to navigate through the file system hierarchy. The flaw represents a classic example of insufficient input validation and improper resource management in web server implementations.
The technical mechanism behind this vulnerability involves the server's processing of HTTP requests where it fails to properly sanitize or limit the number of directory traversal sequences in the requested URI. When an attacker submits a GET request containing numerous "/../" sequences, the server attempts to resolve these path traversal attempts, consuming excessive computational resources and memory allocation. This process can lead to resource exhaustion, application instability, and ultimately system unresponsiveness. The vulnerability operates at the application layer and can be exploited remotely without authentication, making it particularly dangerous for publicly accessible web servers. The flaw aligns with CWE-400, which categorizes improper resource management, and specifically addresses the issue of excessive resource consumption through malformed input processing.
The operational impact of this vulnerability extends beyond simple service disruption, as it can affect the overall availability and reliability of web applications hosted on the affected server. Attackers can exploit this weakness to consume system resources rapidly, potentially causing the server to crash or become unresponsive to legitimate requests. This denial of service condition can be particularly damaging in enterprise environments where web services are critical for business operations, potentially leading to financial losses and reputational damage. The vulnerability demonstrates how seemingly innocuous input patterns can be weaponized to compromise system availability, representing a fundamental weakness in the server's request processing pipeline.
Mitigation strategies for this vulnerability should focus on implementing robust input validation mechanisms and resource limiting configurations within the web server environment. Organizations should configure the server to reject or truncate excessively long URI requests and implement rate limiting to prevent resource exhaustion attacks. Security patches and updates from the vendor should be applied immediately to address the root cause of the vulnerability. Additionally, implementing web application firewalls and intrusion detection systems can help detect and block malicious requests containing excessive directory traversal sequences. The remediation approach should also include monitoring and logging of unusual request patterns to identify potential exploitation attempts. This vulnerability underscores the importance of proper input sanitization and resource management practices in web server implementations, aligning with ATT&CK technique T1499 for resource exhaustion attacks and emphasizing the need for comprehensive security controls in web application environments.