CVE-2011-0166 in Safari
Summary
by MITRE
The HTML5 drag and drop functionality in WebKit in Apple Safari before 5.0.4 allows user-assisted remote attackers to bypass the Same Origin Policy and obtain sensitive information via vectors related to the dragging of content. NOTE: this might overlap CVE-2011-0778.
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Analysis
by VulDB Data Team • 01/26/2025
The vulnerability described in CVE-2011-0166 represents a critical security flaw in Apple Safari's implementation of HTML5 drag and drop functionality within the WebKit rendering engine. This issue affects Safari versions prior to 5.0.4 and exposes a fundamental breach in the browser's security model that could be exploited by remote attackers with minimal user interaction. The vulnerability specifically targets the Same Origin Policy, which serves as one of the core security mechanisms in web browsers that prevents unauthorized access to resources across different domains. When users engage with drag and drop operations involving content from different origins, the flawed implementation fails to properly enforce cross-origin restrictions, creating potential pathways for information disclosure.
The technical nature of this vulnerability stems from how WebKit handles the drag and drop API when processing content from different origins. During drag operations, the browser should strictly enforce that only content from the same origin can be accessed or manipulated, but the flaw allows for cross-origin data leakage through the drag and drop mechanism. Attackers can craft malicious web pages that utilize drag and drop functionality to indirectly access sensitive information from other domains or origins that should normally be restricted. This exploitation occurs when users interact with compromised web content that triggers the vulnerable drag and drop code path, making the attack vector user-assisted rather than fully automated. The vulnerability's classification aligns with CWE-200, which covers "Information Exposure" and specifically addresses situations where sensitive information is disclosed through improper access controls.
The operational impact of this vulnerability extends beyond simple information disclosure, as it fundamentally undermines the security boundaries that web browsers establish between different origins. When an attacker successfully exploits this vulnerability, they can potentially access cookies, local storage data, or other sensitive information that should be isolated between different web domains. The attack scenario typically involves a user visiting a malicious website that contains carefully crafted HTML5 drag and drop code designed to access content from legitimate sites that the user has previously visited or is currently authenticated with. This creates a serious privacy and security risk for users who browse the web with Safari versions affected by this vulnerability, particularly in environments where sensitive data might be stored in browser storage mechanisms. The vulnerability's potential overlap with CVE-2011-0778 indicates that similar cross-origin access issues may exist within the same browser component, suggesting a broader architectural weakness in Safari's handling of cross-origin operations.
Mitigation strategies for this vulnerability require immediate patching of affected Safari versions to 5.0.4 or later, which contains the necessary security fixes to properly enforce Same Origin Policy restrictions during drag and drop operations. System administrators should also implement comprehensive monitoring for suspicious drag and drop activity patterns that might indicate exploitation attempts, particularly in environments where users access sensitive information through Safari. Organizations should consider deploying web application firewalls or content security policies that can detect and block malicious drag and drop operations, though these measures may not fully prevent exploitation given the nature of the vulnerability. The remediation process should include user education about the risks of visiting untrusted websites and the importance of keeping browser software updated, as this vulnerability demonstrates how seemingly benign web features can be weaponized to bypass fundamental security protections. This case highlights the critical importance of thorough security testing for web standards implementations and the potential for standard web APIs to introduce security vulnerabilities when not properly enforced by browser vendors.