CVE-2015-3660 in Safari
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the PDF functionality in WebKit in Apple Safari before 6.2.7, 7.x before 7.1.7, and 8.x before 8.0.7 allows remote attackers to inject arbitrary web script or HTML via a crafted URL in embedded PDF content.
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Analysis
by VulDB Data Team • 05/23/2022
This cross-site scripting vulnerability exists within the PDF rendering functionality of Apple Safari's WebKit engine, representing a critical security flaw that affects multiple versions of the browser. The vulnerability specifically targets how Safari processes embedded PDF content within web pages, creating an attack vector where malicious actors can inject arbitrary web scripts or HTML code through carefully crafted URLs. The flaw manifests when Safari encounters PDF content that contains specially constructed URLs, allowing attackers to execute malicious code in the context of the user's browsing session.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within WebKit's PDF processing components. When Safari encounters embedded PDF objects, it fails to properly sanitize URL parameters within the PDF content, enabling attackers to embed malicious URLs that execute upon user interaction with the PDF. This issue falls under the CWE-79 category of Cross-Site Scripting, specifically representing a reflected XSS vulnerability where the malicious payload is reflected back to the user through the PDF rendering process. The vulnerability is particularly dangerous because it operates within the context of the user's browsing session, potentially allowing attackers to access sensitive cookies, session tokens, or perform actions on behalf of the user.
The operational impact of this vulnerability extends beyond simple script execution, as it can be leveraged for more sophisticated attacks including session hijacking, credential theft, and phishing operations. Attackers can craft malicious PDFs that, when viewed in affected Safari versions, automatically redirect users to malicious domains or inject malicious scripts that harvest user data. The vulnerability affects users across multiple Safari versions including pre-6.2.7, pre-7.1.7, and pre-8.0.7 releases, creating a substantial attack surface given the widespread use of these browser versions. This vulnerability aligns with ATT&CK technique T1566.001 for credential access through phishing and T1211 for exploitation of web applications, making it particularly dangerous in enterprise environments where users may be exposed to malicious PDF content through various attack vectors.
Mitigation strategies should focus on immediate browser updates to patched versions, as Apple released security updates addressing this specific vulnerability. Organizations should implement web application firewalls and content filtering solutions to detect and block suspicious PDF content before it reaches users. Additionally, security awareness training should emphasize the dangers of opening PDF files from untrusted sources, particularly when they are embedded within web pages. Network administrators should consider implementing sandboxing mechanisms for PDF viewing and monitoring for suspicious URL patterns in PDF content. The vulnerability demonstrates the importance of maintaining up-to-date browser software and highlights the need for robust input validation in web rendering engines. Security teams should also consider implementing CSP (Content Security Policy) headers to limit script execution and prevent the successful exploitation of XSS vulnerabilities like this one.