CVE-2002-1236 in BEFSR41
Summary
by MITRE
The remote management web server for Linksys BEFSR41 EtherFast Cable/DSL Router before firmware 1.42.7 allows remote attackers to cause a denial of service (crash) via an HTTP request to Gozila.cgi without any arguments.
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Analysis
by VulDB Data Team • 09/15/2024
The vulnerability identified as CVE-2002-1236 affects the remote management web server component of Linksys BEFSR41 EtherFast Cable/DSL Router devices running firmware versions prior to 1.42.7. This represents a classic buffer overflow condition that manifests through improper input validation within the web server's handling of HTTP requests. The specific exploitation vector targets the Gozila.cgi script which serves as the primary interface for remote administration of the router's configuration parameters. The flaw arises from the web server's failure to properly validate or sanitize input parameters when processing HTTP requests, creating a pathway for malicious actors to trigger system instability.
The technical implementation of this vulnerability stems from the router's web server software failing to implement adequate bounds checking on incoming HTTP request parameters. When an attacker submits an HTTP request to the Gozila.cgi endpoint without providing any arguments, the web server processes this malformed input without proper validation mechanisms. This lack of input sanitization allows the attacker to manipulate the server's memory handling routines, ultimately leading to a system crash or complete denial of service condition. The vulnerability operates at the application layer and demonstrates a fundamental weakness in the router's web interface security architecture.
From an operational perspective, this vulnerability presents a significant risk to network availability and reliability for affected organizations. The denial of service condition impacts the router's ability to provide network connectivity services to connected devices, potentially disrupting business operations and network access for multiple users. The exploitability of this vulnerability is relatively straightforward, requiring only basic HTTP request capabilities to execute the attack, making it accessible to adversaries with minimal technical expertise. This vulnerability directly impacts the router's availability and can result in extended network downtime until the device is manually rebooted or the firmware is updated.
The vulnerability maps to CWE-121, which describes stack-based buffer overflow conditions, and aligns with ATT&CK technique T1499.004 for network denial of service attacks. Organizations should implement immediate mitigations including firmware updates to version 1.42.7 or later, which contain patches addressing the input validation flaws in the web server component. Network segmentation and access control measures can help limit exposure by restricting direct access to router management interfaces from untrusted networks. Additionally, implementing network monitoring solutions that can detect anomalous HTTP request patterns targeting the Gozila.cgi endpoint can provide early warning of potential exploitation attempts. The remediation process should include comprehensive testing of updated firmware in controlled environments before deployment to production networks to ensure continued functionality and prevent unintended service disruptions.