CVE-2008-4485 in Security Gateway OS
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the ICAP patience page in Blue Coat Security Gateway OS (SGOS) 4.2 before 4.2.9, 5.2 before 5.2.5, and 5.3 before 5.3.1.7 allows remote attackers to inject arbitrary web script or HTML via the URL.
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Analysis
by VulDB Data Team • 08/20/2019
The CVE-2008-4485 vulnerability represents a critical cross-site scripting flaw in Blue Coat Security Gateway OS software that affects multiple versions including SGOS 4.2 before 4.2.9, 5.2 before 5.2.5, and 5.3 before 5.3.1.7. This vulnerability specifically targets the ICAP patience page functionality within the security gateway infrastructure, creating a significant attack surface for remote threat actors. The flaw resides in the improper handling of user-supplied input within the ICAP protocol implementation, which is commonly used for content inspection and filtering in web proxy environments. The vulnerability allows attackers to inject malicious scripts or HTML code through the URL parameter, effectively bypassing the security controls that the Blue Coat appliance is designed to enforce.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious URL containing script code that gets processed by the ICAP patience page without proper sanitization or encoding. This lack of input validation creates an environment where malicious payloads can be executed in the context of a victim's browser session, potentially leading to session hijacking, credential theft, or redirection to malicious websites. The vulnerability manifests as a classic XSS flaw, specifically categorized under CWE-79 which defines improper neutralization of input during web page generation. The attack vector is particularly concerning because it leverages the legitimate ICAP protocol functionality that administrators expect to be secure, making detection more difficult for network security teams who may not immediately suspect the patience page as an attack surface.
The operational impact of this vulnerability extends beyond simple script injection, as it can compromise the integrity of the entire security infrastructure. When attackers successfully exploit this flaw, they can manipulate the user experience of administrators and end users interacting with the Blue Coat appliance, potentially leading to unauthorized access to sensitive network monitoring data or disruption of security services. The vulnerability affects organizations that rely on Blue Coat appliances for web filtering, content inspection, and security policy enforcement, creating a scenario where the very tools designed to protect against web-based attacks become vectors for exploitation. This creates a paradoxical security situation where the defensive infrastructure itself becomes compromised, potentially allowing attackers to bypass other security controls that the appliance is supposed to provide.
Organizations affected by this vulnerability should prioritize immediate remediation through official firmware updates provided by Blue Coat, as these patches address the root cause by implementing proper input validation and output encoding for ICAP protocol parameters. Network administrators should also consider implementing additional monitoring for suspicious URL patterns that might indicate exploitation attempts, particularly focusing on unusual characters or script tags in ICAP-related requests. The remediation process should include comprehensive testing of the updated firmware to ensure that legitimate ICAP functionality remains intact while addressing the XSS vulnerability. Security teams should also review their incident response procedures to prepare for potential exploitation scenarios, as this vulnerability could be used to establish persistent access points within the network infrastructure. This vulnerability aligns with ATT&CK technique T1566.002 for social engineering through malicious content, and represents a critical weakness in the web application security posture of organizations relying on legacy Blue Coat appliances that may not receive continued support or updates.