CVE-2011-0169 in Safari
Summary
by MITRE
WebKit in Apple Safari before 5.0.4, when the Web Inspector is used, does not properly handle the window.console._inspectorCommandLineAPI property, which allows user-assisted remote attackers to bypass the Same Origin Policy and conduct cross-site scripting (XSS) attacks via a crafted web site.
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Analysis
by VulDB Data Team • 01/26/2025
The vulnerability described in CVE-2011-0169 represents a critical security flaw in Apple Safari's WebKit rendering engine that existed prior to version 5.0.4. This issue specifically manifests when the Web Inspector functionality is active, creating a dangerous condition that undermines fundamental web security mechanisms. The vulnerability exploits a design flaw in how Safari handles the window.console._inspectorCommandLineAPI property, which serves as an internal debugging interface that should remain inaccessible to regular web content. When this property is improperly managed, it creates an unintended attack surface that malicious actors can leverage to execute arbitrary code within the context of the user's browsing session.
The technical exploitation of this vulnerability stems from Safari's insufficient validation of the window.console._inspectorCommandLineAPI property when the Web Inspector is enabled. This property is intended to provide developers with access to debugging capabilities through the inspector interface, but when improperly handled, it allows attackers to inject malicious JavaScript code that can bypass the browser's Same Origin Policy enforcement mechanisms. The Same Origin Policy is a fundamental security principle that prevents scripts from one origin from accessing resources from another origin, and its circumvention creates a pathway for cross-site scripting attacks. This flaw operates under CWE-20, which describes improper input validation, and more specifically aligns with CWE-94, representing improper control of generation of code, as the vulnerability enables unauthorized code execution through manipulation of the console API.
The operational impact of this vulnerability extends beyond simple XSS exploitation, as it allows attackers to execute arbitrary commands with the privileges of the user's browsing session. This creates a significant risk for users who may inadvertently visit compromised websites while having the Web Inspector enabled, which is often the case for developers and power users who frequently use this debugging feature. The vulnerability is particularly dangerous because it requires minimal user interaction beyond visiting a malicious website, making it a prime candidate for drive-by download attacks. Attackers can craft web pages that automatically execute malicious payloads when the Web Inspector is active, potentially leading to session hijacking, data theft, or further compromise of the user's system. The attack vector aligns with ATT&CK technique T1059.007, which involves the use of scripting languages for execution, and T1566, representing the use of malicious websites for initial access.
Mitigation strategies for this vulnerability require a multi-layered approach that addresses both the immediate security gap and broader browser security practices. Users should immediately update to Safari version 5.0.4 or later, which contains the necessary patches to properly handle the window.console._inspectorCommandLineAPI property. System administrators should consider implementing security policies that disable the Web Inspector feature in enterprise environments where users may be exposed to untrusted content. Additionally, web developers should be aware that enabling the Web Inspector during development creates potential attack vectors that must be carefully managed. The vulnerability demonstrates the importance of proper input validation and the need for comprehensive security testing of browser features that provide debugging access. Organizations should also consider implementing content security policies and regular security assessments to identify similar vulnerabilities that may exist in other browser components or web applications. The fix implemented by Apple involved strengthening the validation of console API access and ensuring that debugging interfaces cannot be manipulated to execute unauthorized code, which aligns with security best practices outlined in OWASP and other industry standards for web application security.