CVE-2011-4689 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 6 through 9 does not prevent capture of data about the times of Same Origin Policy violations during IFRAME loading attempts, which makes it easier for remote attackers to determine whether a document exists in the browser cache via crafted JavaScript code.
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Analysis
by VulDB Data Team • 01/05/2025
This vulnerability in Microsoft Internet Explorer versions 6 through 9 represents a significant information disclosure flaw that exploits the browser's handling of Same Origin Policy violations during cross-domain iframe loading operations. The issue stems from the browser's inability to properly sanitize timing information related to security policy violations, specifically when attempting to load iframe content from different origins. When a JavaScript attack vector attempts to load content from a different domain within an iframe, the browser records timing data about these failed attempts, including the duration of the policy violation events. This timing information becomes accessible to malicious scripts running in the context of the same origin, creating a covert channel that can be exploited to infer cache state information.
The technical implementation of this vulnerability occurs at the browser's security enforcement layer where Same Origin Policy violations are logged and measured. When Internet Explorer encounters an iframe loading attempt that violates the same origin policy, it records timestamps and timing metrics that reflect the browser's internal processing of these security violations. These timing measurements are not properly isolated from the JavaScript execution environment, allowing attacker-controlled code to access this data through carefully crafted JavaScript functions. The vulnerability specifically affects versions 6 through 9 of Internet Explorer, representing a widespread issue across a significant portion of the browser market during that era.
The operational impact of this vulnerability extends beyond simple information leakage, as it enables sophisticated cache poisoning attacks and fingerprinting techniques. Attackers can leverage the timing information to determine whether specific resources exist in the browser cache, which can be used to identify user behavior patterns, track browsing history, or even exploit other cache-related vulnerabilities. This capability significantly undermines the security model of web browsers by creating a side-channel attack vector that bypasses traditional security boundaries. The vulnerability aligns with CWE-200, which addresses information exposure through side channels, and represents a classic example of how seemingly innocuous security logging mechanisms can create exploitable information leaks. The attack surface is particularly concerning given that Internet Explorer 6 through 9 were widely deployed in enterprise environments and consumer markets during the period when this vulnerability existed.
Mitigation strategies for this vulnerability require a multi-layered approach that addresses both the immediate security implications and the underlying architectural flaw. Browser vendors should implement proper isolation of timing information related to security violations, ensuring that such data cannot be accessed through JavaScript execution contexts. Network administrators should consider implementing additional security controls such as content security policies and strict origin validation mechanisms to limit the potential impact of such attacks. The vulnerability demonstrates the importance of proper sandboxing and memory isolation in web browsers, particularly when handling security-sensitive operations. Organizations should also implement regular security assessments to identify similar timing-based side-channel vulnerabilities in their browser environments. This issue highlights the need for comprehensive security testing that includes timing and side-channel attack vectors, as outlined in the ATT&CK framework's techniques for information gathering and reconnaissance activities. The vulnerability serves as a reminder that even seemingly benign browser operations can create security risks when not properly isolated from user-controlled execution environments.