CVE-2017-5075 in Chrome
Summary
by MITRE
Inappropriate implementation in CSP reporting in Blink in Google Chrome prior to 59.0.3071.86 for Linux, Windows, and Mac, and 59.0.3071.92 for Android, allowed a remote attacker to obtain the value of url fragments via a crafted HTML page.
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Analysis
by VulDB Data Team • 01/04/2023
The vulnerability identified as CVE-2017-5075 represents a critical security flaw in the Content Security Policy (CSP) reporting implementation within the Blink rendering engine used by Google Chrome. This issue affects multiple operating systems and platforms, including Linux, Windows, Mac, and Android versions prior to specific patch releases. The flaw stems from an improper handling of URL fragment values during CSP violation reporting processes, creating an unexpected information disclosure channel that could be exploited by remote attackers.
The technical implementation error occurs within the Blink engine's CSP reporting mechanism where URL fragments are inadvertently exposed when browsers process CSP violation reports. This vulnerability specifically impacts how Chrome handles the reporting of CSP violations that involve URLs containing fragment identifiers. When a malicious HTML page triggers a CSP violation, the browser's reporting functionality fails to properly sanitize or strip fragment components from URLs before transmitting them in violation reports. The flaw allows attackers to craft specially designed HTML pages that can extract fragment values from target URLs, effectively bypassing normal security boundaries that should prevent such information leakage.
The operational impact of this vulnerability extends beyond simple information disclosure, as URL fragments often contain sensitive data or session identifiers that attackers can leverage for further exploitation. Attackers can construct malicious web pages that, when loaded in vulnerable Chrome browsers, will trigger CSP violations that reveal fragment information from other websites. This creates a potential vector for cross-site scripting attacks, session hijacking, or the extraction of sensitive parameters that are typically intended to remain private within URL fragments. The vulnerability particularly affects scenarios where users navigate between different domains while maintaining session state through fragment identifiers, making it a significant concern for web applications that rely on such mechanisms for security purposes.
This vulnerability aligns with CWE-200, which addresses "Information Exposure," and demonstrates how improper handling of user input during security reporting processes can create unexpected disclosure channels. The flaw also relates to ATT&CK technique T1071.004, which covers "Application Layer Protocol: DNS," as the information leakage can be used to reconstruct network traffic patterns and potentially identify target systems. Organizations should implement immediate mitigations including updating to patched Chrome versions, configuring stricter CSP policies that limit fragment exposure, and monitoring for suspicious CSP violation reports. The vulnerability underscores the importance of proper input sanitization in security-critical components and highlights the need for comprehensive testing of security reporting mechanisms to prevent unintended information flows that could compromise user privacy and system security.