CVE-2001-0521 in eSafe Gateway
Summary
by MITRE
Aladdin eSafe Gateway versions 3.0 and earlier allows a remote attacker to circumvent HTML SCRIPT filtering via the UNICODE encoding of SCRIPT tags within the HTML document.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 12/09/2024
The vulnerability described in CVE-2001-0521 represents a significant security flaw in Aladdin eSafe Gateway versions 3.0 and earlier, specifically targeting the HTML SCRIPT tag filtering mechanism. This issue stems from an insufficient validation process that fails to properly decode and inspect UNICODE encoded content within HTML documents. The eSafe Gateway serves as a security appliance designed to filter and sanitize web content before it reaches end users, particularly focusing on preventing malicious script execution. When attackers exploit this vulnerability, they can bypass the intended security controls by encoding SCRIPT tags using UNICODE character sequences, effectively evading the filtering mechanisms that should prevent cross-site scripting attacks. The flaw operates at the application layer and specifically targets the content inspection capabilities of the security gateway.
The technical implementation of this vulnerability involves the manipulation of HTML encoding standards to circumvent security controls. When the eSafe Gateway processes HTML content, it fails to properly normalize or decode UNICODE sequences that represent SCRIPT tags, allowing malicious code to pass through undetected. This represents a classic case of input validation failure where the system does not adequately handle encoded content. The vulnerability can be classified under CWE-180, which deals with insufficient input validation, and more specifically aligns with CWE-77, which addresses command injection vulnerabilities. Attackers can leverage this weakness by crafting malicious HTML documents that contain SCRIPT tags encoded in UNICODE format, where each character in the SCRIPT tag is represented using multiple bytes or escape sequences that the filtering system fails to properly decode and analyze. The attack vector is entirely remote, meaning an attacker can exploit this vulnerability without requiring local access to the system.
The operational impact of CVE-2001-0521 is severe and directly affects the core security functionality of the eSafe Gateway appliance. Organizations relying on this security solution for protecting their networks against cross-site scripting attacks face a critical risk where malicious scripts can execute in users' browsers without detection. This vulnerability undermines the fundamental purpose of the security gateway, which is to act as a protective barrier against web-based attacks. The potential for exploitation includes the execution of malicious JavaScript code, which could lead to session hijacking, data theft, or further compromise of the affected systems. From an attacker's perspective, this vulnerability aligns with ATT&CK technique T1059.007 for scripting, specifically targeting the execution of malicious code through web-based vectors. The impact extends beyond individual attacks to potentially compromise entire network perimeters that depend on the eSafe Gateway for web content filtering. Organizations may experience unauthorized access to sensitive data, disruption of services, and potential compliance violations if their security infrastructure fails to properly filter malicious content.
Mitigation strategies for this vulnerability require immediate attention and implementation of multiple defensive measures. The primary solution involves updating to a newer version of the Aladdin eSafe Gateway that properly handles UNICODE decoding and normalization of HTML content. Organizations should also implement additional content inspection mechanisms that validate encoded content through multiple layers of analysis rather than relying solely on single-pass filtering. Network administrators should consider implementing additional security controls such as web application firewalls, enhanced content filtering, and regular security audits of their web security infrastructure. The implementation of proper input sanitization techniques that normalize all encoded content before analysis can help prevent similar issues. Security teams should also establish monitoring procedures to detect and respond to potential exploitation attempts. From a compliance perspective, this vulnerability highlights the importance of maintaining up-to-date security solutions and conducting regular vulnerability assessments. Organizations should also implement defense-in-depth strategies that do not rely on a single point of failure for web content filtering, ensuring that multiple security controls work together to provide comprehensive protection against web-based attacks.