CVE-2014-1346 in Safari
Summary
by MITRE
WebKit, as used in Apple Safari before 6.1.4 and 7.x before 7.0.4, does not properly interpret Unicode encoding, which allows remote attackers to spoof a postMessage origin, and bypass intended restrictions on sending a message to a connected frame or window, via crafted characters in a URL.
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Analysis
by VulDB Data Team • 12/26/2024
The vulnerability identified as CVE-2014-1346 represents a critical security flaw in WebKit's Unicode handling mechanisms within Apple Safari browsers. This issue stems from the browser's improper interpretation of Unicode encoding standards, specifically affecting versions prior to 6.1.4 for Safari 6.x and 7.0.4 for Safari 7.x. The flaw manifests in how the browser processes and validates Unicode characters within URL structures, creating a pathway for malicious actors to exploit the postMessage API's origin validation mechanisms.
The technical core of this vulnerability lies in the inconsistent Unicode normalization behavior within WebKit's URL parsing engine. When processing URLs containing crafted Unicode characters, the browser fails to properly canonicalize these sequences, allowing attackers to manipulate the origin parameter that postMessage uses to enforce cross-origin security restrictions. This misinterpretation enables the bypass of intended security boundaries between different frames or windows, effectively undermining the same-origin policy that forms the foundation of web security.
The operational impact of this vulnerability is significant as it allows remote attackers to perform cross-site scripting attacks by spoofing the origin of postMessage calls. An attacker could craft a malicious URL containing specific Unicode sequences that appear legitimate to the browser's origin validation system while actually representing a different domain or frame context. This capability enables unauthorized communication between frames or windows that should be isolated, potentially allowing for data exfiltration, session hijacking, or the execution of malicious code within targeted applications that rely on postMessage for secure communication between components.
The vulnerability aligns with CWE-184, which addresses incomplete or missing Unicode normalization in security-relevant contexts, and relates to ATT&CK technique T1056.001 for Input Injection and T1566.001 for Phishing. The flaw demonstrates how Unicode handling inconsistencies can be weaponized in browser-based attacks, particularly affecting web applications that depend on proper origin validation for secure cross-origin communication. Organizations using affected Safari versions face increased risk of exploitation in scenarios involving web applications that utilize postMessage for inter-frame communication or integration with external services, making this vulnerability particularly dangerous in enterprise environments where such communication patterns are common.
Mitigation strategies for CVE-2014-1346 require immediate patching of affected Safari versions to the recommended secure releases, along with implementing additional security measures such as Content Security Policy headers, proper input validation for URL parameters, and monitoring for suspicious postMessage activity. Browser vendors and security teams should also consider implementing more robust Unicode normalization routines in their URL parsing implementations to prevent similar vulnerabilities from emerging in the future, particularly in systems that handle cross-origin communication mechanisms.