CVE-2015-5236 in IcedTea-Web
Summary
by MITRE • 07/07/2022
It was discovered that the IcedTea-Web used codebase attribute of the <applet> tag on the HTML page that hosts Java applet in the Same Origin Policy (SOP) checks. As the specified codebase does not have to match the applet's actual origin, this allowed malicious site to bypass SOP via spoofed codebase value.
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Analysis
by VulDB Data Team • 07/20/2022
The vulnerability described in CVE-2015-5236 represents a critical security flaw in the IcedTea-Web implementation that undermines the fundamental Same Origin Policy protections within web browsers. This issue specifically affects how Java applets are handled when executed within HTML pages, creating a significant bypass mechanism that allows malicious actors to circumvent security controls designed to prevent cross-origin resource access. The vulnerability stems from the improper handling of the codebase attribute within the applet tag, which is used to specify the base URL for loading applet classes and resources.
The technical flaw in IcedTea-Web lies in its failure to properly validate the codebase attribute against the actual origin of the applet being loaded. When a web page contains an applet tag with a codebase attribute, the browser should enforce strict origin checking to ensure that resources are only loaded from the expected domain. However, the vulnerable implementation allows attackers to specify any codebase value in the HTML, regardless of the actual location where the applet is hosted. This creates a scenario where a malicious website can manipulate the codebase attribute to point to a trusted domain while actually serving malicious content from an untrusted source.
The operational impact of this vulnerability is severe as it enables attackers to perform cross-origin resource access attacks that would normally be blocked by browser security mechanisms. An attacker could host a malicious applet on one domain while setting the codebase attribute to point to a legitimate, trusted domain that the victim's browser would normally trust. This spoofing technique allows the malicious code to bypass the same origin policy restrictions that are essential for preventing unauthorized access to sensitive data and system resources. The vulnerability essentially creates a pathway for attackers to execute arbitrary code with the privileges of the trusted domain, potentially leading to data theft, privilege escalation, or complete system compromise.
This vulnerability maps directly to CWE-284: Improper Access Control and aligns with several ATT&CK techniques including T1059.007: Command and Scripting Interpreter: Visual Basic and T1211: Exploitation for Privilege Escalation. The flaw demonstrates a classic improper access control issue where the system fails to properly validate the source of applet resources. Organizations using IcedTea-Web are particularly vulnerable because the issue affects the core security mechanisms of Java applet execution, making it difficult to detect and mitigate without proper patching. The vulnerability also represents a breakdown in the principle of least privilege, as the system allows code to execute with elevated permissions based on a misleading codebase attribute rather than the actual security context of the resource being loaded.
The recommended mitigations for CVE-2015-5236 include immediate patching of IcedTea-Web installations to versions that properly enforce codebase validation against actual applet origins. System administrators should also implement strict content security policies that limit the domains from which applets can be loaded, and consider disabling Java applet execution entirely in web browsers where possible. Additionally, organizations should monitor for suspicious codebase attribute values in their web applications and implement proper input validation to prevent malicious manipulation of applet attributes. The vulnerability highlights the importance of proper origin validation in security-critical components and underscores the need for comprehensive testing of security mechanisms in web application frameworks.