CVE-2015-2398 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 8 through 11 allows remote attackers to bypass the XSS filter via a crafted attribute of an element in an HTML document, aka "Internet Explorer XSS Filter Bypass Vulnerability."
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Analysis
by VulDB Data Team • 05/31/2022
The vulnerability identified as CVE-2015-2398 represents a critical security flaw in Microsoft Internet Explorer versions 8 through 11 that undermines the browser's cross-site scripting (XSS) protection mechanisms. This issue allows remote attackers to execute malicious scripts against users by exploiting a weakness in how the browser's XSS filter processes HTML attributes, effectively bypassing the intended security controls designed to prevent injection attacks. The flaw specifically targets the filter's ability to properly sanitize HTML elements and their attributes, creating a pathway for attackers to deliver malicious payloads that would normally be blocked by the browser's security features.
The technical implementation of this vulnerability stems from insufficient validation and sanitization of HTML attributes within Internet Explorer's XSS filter subsystem. When processing HTML documents containing crafted attributes, the browser fails to properly recognize and neutralize potentially malicious content that could be used to execute scripts in the context of the user's session. This bypass occurs because the XSS filter does not adequately account for various encoding techniques or attribute manipulation methods that attackers can employ to circumvent the security checks. The vulnerability operates at the application layer and specifically affects the browser's HTML parsing and sanitization logic, making it particularly dangerous as it directly impacts the core security features that protect users from common web-based attacks.
The operational impact of CVE-2015-2398 extends beyond simple script execution, as it enables attackers to perform a range of malicious activities including session hijacking, data theft, and redirection to malicious sites. Users browsing the web with affected Internet Explorer versions become vulnerable to sophisticated phishing attacks where attackers can craft HTML documents that appear legitimate but contain hidden malicious attributes. The vulnerability is particularly concerning because it affects multiple versions of Internet Explorer, creating a broad attack surface that includes legacy systems that may not receive timely updates. Security researchers have noted that this flaw can be leveraged in combination with other techniques to create more complex attack vectors, potentially allowing for privilege escalation or persistent access to user systems.
Organizations and individuals should implement multiple layers of defense to mitigate the risks associated with this vulnerability, including immediate patching of affected systems and deployment of web application firewalls to provide additional protection. The vulnerability aligns with CWE-79, which describes cross-site scripting flaws in web applications, and can be categorized under ATT&CK technique T1059.001 for command and scripting interpreter, as it enables attackers to execute malicious code through browser-based vectors. Additional mitigations include implementing strict content security policies, enabling enhanced security features within Internet Explorer, and conducting regular security assessments to identify potentially vulnerable web applications that may be exploited through this vulnerability. The threat landscape surrounding this vulnerability demonstrates the importance of maintaining current security patches and employing defense-in-depth strategies to protect against browser-based attacks that target fundamental security controls.