CVE-2015-3752 in Safari
Summary
by MITRE
The Content Security Policy implementation in WebKit in Apple Safari before 6.2.8, 7.x before 7.1.8, and 8.x before 8.0.8, as used in iOS before 8.4.1 and other products, does not properly restrict cookie transmission for report requests, which allows remote attackers to obtain sensitive information via vectors involving (1) a cross-origin request or (2) a private-browsing request.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 11/24/2024
The vulnerability described in CVE-2015-3752 represents a critical flaw in the Content Security Policy (CSP) implementation within WebKit-based browsers, specifically affecting Apple Safari versions prior to the mentioned patches. This issue resides in the browser's handling of cookie transmission during CSP violation report requests, creating a significant information disclosure risk that could be exploited by remote attackers. The vulnerability affects multiple browser versions and operating systems, including iOS before 8.4.1, making it a widespread concern across Apple's ecosystem. The flaw specifically impacts how browsers manage cookie data when sending violation reports, potentially exposing sensitive session information to unauthorized parties.
The technical root cause of this vulnerability lies in the improper restriction of cookie transmission within the CSP reporting mechanism. When a web page violates a Content Security Policy directive, the browser is supposed to send a violation report to a specified endpoint. However, in affected Safari versions, the implementation fails to properly sanitize or restrict the cookie data that gets included in these violation reports. This occurs during cross-origin requests or private browsing sessions where cookie handling should be more restrictive. The flaw essentially allows cookies to be transmitted in violation reports even when they shouldn't be, creating a pathway for sensitive information leakage. This issue is classified under CWE-200, which deals with information exposure, and specifically relates to improper restriction of information flow within browser security mechanisms.
The operational impact of this vulnerability is significant as it enables remote attackers to harvest sensitive session cookies and other authentication-related information from users' browsers. Attackers can exploit this by crafting malicious web pages that trigger CSP violations, then capture the violation reports containing cookie data. This information can be used for session hijacking, authentication bypass attacks, or to impersonate users within targeted applications. The vulnerability is particularly dangerous in private browsing modes where users expect enhanced privacy protections, as the flaw undermines these security assumptions. The attack vectors involve either cross-origin requests that trigger violations or private browsing scenarios where cookie restrictions are normally more stringent, making the exploitation more likely to succeed in real-world scenarios.
Mitigation strategies for this vulnerability primarily involve applying the vendor-provided security updates that address the CSP implementation flaw. Users should immediately upgrade to Safari versions 6.2.8, 7.1.8, or 8.0.8 respectively, along with the corresponding iOS updates. Organizations should also implement network-level protections such as strict CSP policies that limit cookie transmission in violation reports and monitor for unusual violation report patterns. Browser administrators can consider disabling CSP violation reporting for sensitive applications or implementing additional layers of cookie management. The vulnerability highlights the importance of proper cookie handling in security reporting mechanisms and underscores the need for comprehensive testing of security features in web browsers. From an ATT&CK perspective, this vulnerability relates to T1566, credential access through web application attacks, and T1071, application layer protocol usage for data exfiltration, making it a critical concern for both endpoint and network security teams.