CVE-2017-5096 in Chrome
Summary
by MITRE
Insufficient policy enforcement during navigation between different schemes in Google Chrome prior to 60.0.3112.78 for Android allowed a remote attacker to perform cross origin content download via a crafted HTML page, related to intents.
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Analysis
by VulDB Data Team • 01/05/2023
The vulnerability identified as CVE-2017-5096 represents a critical security flaw in Google Chrome's handling of cross-origin navigation on Android devices. This issue stems from insufficient policy enforcement mechanisms that govern how the browser manages transitions between different URI schemes. The flaw specifically affects Chrome versions prior to 60.0.3112.78, creating a pathway for remote attackers to exploit the browser's intent system for malicious purposes. The vulnerability leverages the Android intent framework which is designed to facilitate communication between different applications and components, but fails to properly validate scheme transitions within the browser context.
The technical implementation of this vulnerability involves a sophisticated attack vector that manipulates Chrome's navigation handling when transitioning between different URI schemes such as http, https, and intent schemes. When a user visits a maliciously crafted HTML page, the attacker can leverage the browser's intent system to trigger unauthorized cross-origin content downloads. This occurs because Chrome's policy enforcement mechanisms do not adequately validate or restrict navigation between different schemes, allowing malicious pages to exploit the underlying Android intent infrastructure to access resources that should normally be restricted. The flaw specifically targets the browser's handling of intent-based navigation where the system fails to properly enforce security boundaries between different origin contexts.
The operational impact of this vulnerability extends beyond simple content theft, as it enables attackers to perform unauthorized downloads of sensitive content across origin boundaries. This capability allows threat actors to bypass standard web security mechanisms such as the same-origin policy, potentially accessing data that should be protected by cross-origin restrictions. The attack scenario typically involves a malicious webpage that uses crafted intent URLs to redirect users to unintended destinations, where the browser's intent system is leveraged to download content from different origins without proper authorization. This creates a significant risk for users who may unknowingly access malicious content that triggers these unauthorized downloads, potentially exposing sensitive data or system resources.
This vulnerability maps to CWE-693, which addresses Protection Mechanism Failure, specifically in the context of insufficient policy enforcement. The flaw also aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter: JavaScript, as the exploitation typically occurs through malicious JavaScript code embedded in crafted HTML pages. Additionally, it relates to T1071.004 for Application Layer Protocol: DNS, since the attack may involve DNS resolution manipulation during cross-origin navigation. The vulnerability demonstrates a classic example of how mobile browser security models can be compromised when underlying platform components such as Android intents are not properly integrated with web security policies. Organizations should implement immediate mitigations including updating to Chrome version 60.0.3112.78 or later, implementing network-level restrictions to prevent access to known malicious domains, and educating users about the risks of visiting untrusted websites. The fix implemented by Google involved strengthening the policy enforcement mechanisms during scheme transitions and ensuring proper validation of intent-based navigation to prevent unauthorized cross-origin resource access.