CVE-2010-1393 in Safari
Summary
by MITRE
The Cascading Style Sheets (CSS) implementation in WebKit in Apple Safari before 5.0 on Mac OS X 10.5 through 10.6 and Windows, and before 4.1 on Mac OS X 10.4, allows remote attackers to discover sensitive URLs via an HREF attribute associated with a redirecting URL.
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Analysis
by VulDB Data Team • 09/15/2021
The vulnerability identified as CVE-2010-1393 represents a significant information disclosure flaw within the WebKit rendering engine that powers Apple Safari browsers across multiple operating systems. This issue specifically affects the CSS implementation within WebKit and manifests in versions of Safari prior to 5.0 on Mac OS X 10.5 through 10.6 and Windows platforms, as well as versions before 4.1 on Mac OS X 10.4. The flaw enables remote attackers to potentially uncover sensitive URLs that should remain hidden from users, creating a serious privacy and security risk for affected systems.
The technical mechanism behind this vulnerability involves the improper handling of HREF attributes within CSS contexts, particularly when these attributes are associated with redirecting URLs. When WebKit processes CSS stylesheets containing specific HREF attribute configurations, it fails to properly sanitize or obscure the underlying URL references, allowing attackers to extract information about redirect targets that would normally be protected. This behavior stems from inadequate input validation and output sanitization within the CSS parsing and rendering components of the WebKit engine, creating an information leak channel that can be exploited through crafted web content.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can enable attackers to map internal network structures, discover administrative interfaces, or identify sensitive resources that should remain hidden from external parties. In practical attack scenarios, this vulnerability could be leveraged to uncover redirect chains that lead to internal systems, authentication endpoints, or other sensitive resources that are typically protected by URL obfuscation. The risk is particularly elevated in environments where web applications rely on redirect mechanisms to hide or protect access to sensitive functionality, as this flaw effectively bypasses such protective measures.
Organizations affected by this vulnerability should immediately implement mitigations including updating to patched versions of Safari browsers, as Apple released security updates addressing this specific issue. System administrators should also consider implementing network-level protections such as web application firewalls that can detect and block suspicious URL patterns, though the fundamental fix requires browser updates to address the underlying CSS parsing implementation. The vulnerability aligns with CWE-200, which catalogs information exposure flaws, and could potentially map to ATT&CK technique T1071.004 related to application layer protocol traffic inspection, though the specific vector here is more focused on information leakage through CSS processing rather than active traffic manipulation.
This vulnerability demonstrates the complexity of modern browser security and highlights how seemingly innocuous CSS processing can create significant information disclosure risks. The flaw underscores the importance of comprehensive security testing across all browser components, particularly those handling user-supplied content, and emphasizes that security considerations must extend beyond core functionality to include all parsing and rendering mechanisms. Organizations should conduct thorough vulnerability assessments to identify potential similar issues in other browser components and maintain updated security practices to protect against evolving threats in web-based environments.