CVE-2003-1568 in WebServer
Summary
by MITRE
GoAhead WebServer before 2.1.6 allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via an invalid URL, related to the websSafeUrl function.
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Analysis
by VulDB Data Team • 10/27/2018
The vulnerability identified as CVE-2003-1568 affects the GoAhead WebServer version 2.1.5 and earlier, representing a critical denial of service flaw that can be exploited remotely by attackers. This vulnerability specifically targets the websSafeUrl function within the web server implementation, which fails to properly validate URL inputs before processing them. The flaw manifests when the web server encounters an invalid URL structure that triggers a NULL pointer dereference condition, ultimately leading to the daemon crashing and ceasing operations. This represents a classic example of improper input validation that can be leveraged by malicious actors to disrupt web server availability.
The technical implementation of this vulnerability stems from inadequate error handling within the websSafeUrl function, which is responsible for sanitizing and validating URL parameters before they are processed by the web server. When an attacker crafts a malformed URL that bypasses normal validation routines, the function fails to properly handle the NULL or malformed input, resulting in a pointer dereference that crashes the entire web server daemon. This behavior aligns with CWE-476, which describes NULL pointer dereference vulnerabilities, and represents a fundamental flaw in the server's defensive programming practices. The vulnerability operates at the application layer and can be exploited through standard HTTP requests without requiring authentication or specialized privileges.
From an operational impact perspective, this vulnerability creates significant availability risks for systems running affected versions of GoAhead WebServer. The remote exploitation capability means that attackers can potentially disrupt web services from anywhere on the network, making this a particularly dangerous vulnerability for publicly accessible web servers. The daemon crash results in immediate service interruption, requiring manual intervention to restart the web server process and restore normal operations. Organizations relying on GoAhead WebServer for hosting critical web applications face potential business disruption, revenue loss, and reputational damage when such attacks occur. This vulnerability also creates opportunities for attackers to conduct further reconnaissance or launch additional attacks against compromised systems, as the server downtime can mask other malicious activities.
The recommended mitigation strategy for CVE-2003-1568 involves immediate deployment of the patched GoAhead WebServer version 2.1.6 or later, which includes proper input validation and error handling for the websSafeUrl function. System administrators should also implement network-level protections such as firewall rules that restrict access to web server ports from untrusted networks, and consider deploying intrusion detection systems that can identify and block malformed URL patterns. Additionally, organizations should establish robust monitoring procedures to detect web server crashes or restarts that may indicate exploitation attempts. The vulnerability demonstrates the importance of input validation and defensive programming practices, aligning with ATT&CK technique T1499.004 for network denial of service attacks. Regular security assessments and vulnerability scanning should be conducted to identify similar flaws in other web server implementations, as this vulnerability type remains prevalent in legacy systems and can be exploited by automated scanning tools that target known patterns of web server misconfigurations.