CVE-2009-2066 in Safari
Summary
by MITRE
Apple Safari detects http content in https web pages only when the top-level frame uses https, which allows man-in-the-middle attackers to execute arbitrary web script, in an https site s context, by modifying an http page to include an https iframe that references a script file on an http site, related to "HTTP-Intended-but-HTTPS-Loadable (HPIHSL) pages."
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Analysis
by VulDB Data Team • 09/06/2019
The vulnerability described in CVE-2009-2066 represents a critical security flaw in Apple Safari's handling of mixed content within secure web environments. This issue stems from Safari's inconsistent approach to detecting and blocking insecure HTTP content when users navigate to HTTPS websites. The vulnerability specifically affects how Safari processes top-level frames versus nested frames, creating a significant attack vector for man-in-the-middle adversaries who can exploit the browser's relaxed security controls for embedded content.
The technical flaw manifests when an attacker manipulates an HTTP page to include an HTTPS iframe that references a script file from an HTTP site. This creates what security researchers term "HTTP-Intended-but-HTTPS-Loadable (HPIHSL) pages" where the browser's security model fails to properly isolate content based on the context in which it loads. The vulnerability is particularly dangerous because it allows attackers to execute arbitrary JavaScript code within the secure context of an HTTPS site, effectively bypassing the security mechanisms that should prevent such cross-context execution.
This vulnerability has significant operational impact as it undermines the fundamental security promise of HTTPS encryption and certificate validation. When users visit what appears to be a secure website, they may unknowingly execute malicious code that can capture keystrokes, steal session cookies, or perform other malicious activities. The attack requires only that an attacker can modify content on an HTTP site that is embedded within an HTTPS page, making it particularly effective in scenarios where the attacker controls or can compromise a third-party HTTP resource.
The security implications extend beyond simple content injection, as this vulnerability enables attackers to perform sophisticated attacks such as credential harvesting, session hijacking, and data exfiltration. The flaw relates to CWE-346, which addresses "Improper Verification of Source of a Communication Channel" and aligns with ATT&CK techniques involving credential access and execution within secure contexts. This vulnerability demonstrates the complexity of mixed-content security models and highlights the importance of consistent security enforcement across all content loading mechanisms within web browsers. Organizations and users must understand that the presence of HTTPS on a main page does not guarantee protection against all types of attacks when insecure content is embedded through iframes or other mechanisms, making proper security configuration and monitoring essential for maintaining web application integrity.
The vulnerability also underscores the broader challenge of implementing robust mixed-content policies in web browsers, as the distinction between top-level and nested frame security contexts can create unexpected attack surfaces. This flaw exemplifies why security researchers emphasize the need for comprehensive security models that consider all potential entry points and execution contexts within web applications. The issue serves as a reminder that web security is not merely about protecting the main page but ensuring that all embedded content adheres to the same security standards regardless of how it is loaded or referenced within the browser environment.