CVE-2001-0530 in NetGAP 200
Summary
by MITRE
Spearhead NetGAP 200 and 300 before build 78 allow a remote attacker to bypass file blocking and content inspection via specially encoded URLs which include % characters.
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Analysis
by VulDB Data Team • 07/08/2014
The vulnerability identified as CVE-2001-0530 affects Spearhead NetGAP 200 and 300 firewall appliances prior to build 78, representing a significant security flaw in network traffic inspection and content filtering capabilities. This weakness stems from inadequate handling of URL encoding mechanisms within the appliance's content inspection engine, creating a pathway for malicious actors to circumvent established security controls. The vulnerability specifically targets the appliance's ability to properly parse and evaluate web addresses that contain percent-encoded characters, which are standard components of Uniform Resource Locator syntax used for encoding special characters in web communications.
The technical implementation of this flaw occurs at the application layer where the NetGAP appliance fails to properly decode and validate URL sequences containing % characters before performing content inspection and file blocking operations. When a malicious user crafts a specially encoded URL that includes percent-encoding, the appliance processes these sequences incorrectly, allowing potentially harmful content to pass through security controls that would normally block such traffic. This represents a classic case of improper input validation and sanitization, where the system does not adequately handle malformed or specially crafted input that could be used to exploit the security controls. The vulnerability essentially allows attackers to manipulate the appliance's interpretation of URLs, effectively bypassing the intended security policies.
The operational impact of this vulnerability is substantial as it directly compromises the fundamental security posture of organizations relying on Spearhead NetGAP appliances for network protection. Remote attackers can exploit this weakness to deliver malicious content, bypass content filtering policies, and potentially gain unauthorized access to network resources that would normally be blocked. The vulnerability affects both the file blocking functionality and content inspection capabilities, meaning that malicious downloads, phishing attempts, and other web-based attacks could successfully penetrate the network perimeter. This creates a dangerous situation where organizations believe their security controls are functioning properly while simultaneously allowing harmful traffic to flow through their networks. The remote nature of the attack means that threat actors do not require physical access or local network privileges to exploit this vulnerability, making it particularly concerning for enterprise environments.
Organizations should immediately implement mitigations including updating to the latest available build of Spearhead NetGAP 200 and 300 appliances that address this vulnerability, which aligns with the principle of keeping security software current as recommended by the NIST Cybersecurity Framework. Network administrators should also implement additional monitoring and logging of URL patterns to detect potential exploitation attempts, while applying network segmentation and additional security controls as compensating measures. The vulnerability demonstrates a clear violation of CWE-20, which covers "Improper Input Validation," and represents a technique that could be mapped to ATT&CK tactic TA0011 (Command and Control) through the use of encoded URLs to bypass network controls. Security teams should also consider implementing web application firewalls and additional content inspection mechanisms to provide layered defense against similar encoding-based evasion techniques that may affect other security appliances in their environment.