CVE-2018-20068 in Chrome
Summary
by MITRE
Incorrect handling of 304 status codes in Navigation in Google Chrome prior to 71.0.3578.80 allowed a remote attacker to confuse the user about the origin of the current page via a crafted HTML page.
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Analysis
by VulDB Data Team • 04/27/2020
The vulnerability described in CVE-2018-20068 represents a critical issue in Google Chrome's navigation handling mechanism that specifically pertains to the improper management of HTTP 304 status codes. This flaw existed in Chrome versions prior to 71.0.3578.80 and exploited a fundamental weakness in how the browser processes conditional requests and response handling. The vulnerability stems from Chrome's failure to properly validate or process 304 Not Modified responses during navigation operations, creating a scenario where malicious actors could manipulate the browser's perception of page origins.
The technical implementation of this vulnerability involves the manipulation of HTTP response headers and status codes within the browser's navigation stack. When a web server responds with a 304 status code, it indicates that the requested resource has not been modified since the last request, allowing the browser to use its cached version. However, Chrome's flawed implementation allowed attackers to craft HTML pages that would cause the browser to display misleading information about the current page's origin while maintaining the appearance of legitimate navigation. This creates a deceptive user experience where the browser interface shows one origin while the actual content may be sourced from a different location, effectively enabling phishing attacks or social engineering scenarios.
The operational impact of this vulnerability extends beyond simple user confusion and represents a significant threat to browser security and user trust. Attackers could exploit this weakness to create convincing phishing pages that appear to originate from legitimate websites, potentially deceiving users into entering sensitive information or performing actions they would not normally undertake. The vulnerability specifically targets the user interface elements that display page origins, making it particularly dangerous for credential harvesting attacks or fraud schemes. This type of deception directly violates user expectations of browser security and can lead to successful social engineering campaigns that bypass traditional security measures.
From a cybersecurity perspective, this vulnerability aligns with CWE-200, which addresses information exposure, and represents a failure in proper input validation and response handling. The flaw also relates to ATT&CK technique T1566, which covers phishing campaigns, as it enables attackers to create more convincing deceptive web pages. The vulnerability demonstrates a classic case of improper error handling and response validation in web browser implementations, where the system fails to properly sanitize or validate the information presented to users during navigation operations. This represents a failure in the browser's security model to properly isolate and validate navigation contexts, particularly when dealing with conditional HTTP responses.
The recommended mitigation strategy involves immediate updating of Google Chrome to version 71.0.3578.80 or later, which contains the necessary patches to properly handle 304 status codes during navigation. Organizations should also implement additional security measures including web application firewalls, content security policies, and regular browser updates as part of their security protocols. Network administrators should monitor for potential exploitation attempts and ensure that all endpoints maintain current browser versions to prevent this vulnerability from being exploited in enterprise environments. The fix implemented by Google likely involved stricter validation of HTTP response headers and improved handling of conditional requests to prevent the display of misleading origin information during navigation operations.