CVE-2013-2920 in Chrome
Summary
by MITRE
The DoResolveRelativeHost function in url/url_canon_relative.cc in Google Chrome before 30.0.1599.66 allows remote attackers to cause a denial of service (out-of-bounds read) via a relative URL containing a hostname, as demonstrated by a protocol-relative URL beginning with a //www.google.com/ substring.
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Analysis
by VulDB Data Team • 05/26/2021
The vulnerability described in CVE-2013-2920 represents a critical out-of-bounds read flaw within Google Chrome's URL parsing mechanism that could be exploited to trigger a denial of service condition. This issue resides in the DoResolveRelativeHost function located in the url/url_canon_relative.cc source file, which is part of Chrome's core URL canonicalization library responsible for processing and normalizing web addresses. The vulnerability manifests when Chrome encounters relative URLs containing hostnames, particularly protocol-relative URLs that begin with the double forward slash sequence followed by a hostname such as //www.google.com/. This specific parsing pattern creates a scenario where the application attempts to access memory locations beyond the bounds of allocated buffers during URL resolution operations.
The technical exploitation of this vulnerability occurs through careful crafting of malicious URLs that leverage the protocol-relative URL syntax to manipulate the URL canonicalization process. When Chrome processes such malformed URLs, the DoResolveRelativeHost function fails to properly validate the boundaries of hostname data within the relative URL structure, leading to an out-of-bounds memory read operation. This type of flaw falls under the CWE-125 vulnerability category, which specifically addresses out-of-bounds read conditions that can result in information disclosure, system instability, or potential privilege escalation depending on the execution context. The vulnerability's impact is amplified by its location within Chrome's fundamental URL processing pipeline, meaning that any web content that triggers this code path could potentially exploit the flaw regardless of the user's browsing context or security settings.
From an operational perspective, this vulnerability presents a significant risk to Chrome users as it can be triggered through standard web browsing activities without requiring any special privileges or user interaction beyond visiting a malicious website. The denial of service condition typically manifests as browser crashes or application instability, effectively disrupting user sessions and potentially providing attackers with a means to perform persistent disruption attacks against targeted users or systems. The vulnerability's exploitation is particularly concerning because it operates at the URL parsing level, meaning that even innocuous-looking web addresses could contain embedded malicious URL structures that trigger the flaw when processed by Chrome's rendering engine. This characteristic places the vulnerability within the ATT&CK framework's T1211 category for exploitation of remote services and T1059 for command and scripting interpreters, as it enables attackers to craft malicious web content that can be delivered through standard web protocols.
The mitigation strategy for CVE-2013-2920 involves immediate patching of affected Chrome versions to the recommended minimum version 30.0.1599.66 or later, which contains the necessary code fixes to properly validate hostname boundaries during relative URL processing. Security administrators should prioritize deployment of these updates across all managed Chrome installations and implement automated patch management systems to ensure timely remediation. Additionally, organizations may consider implementing web application firewalls or content filtering solutions that can detect and block protocol-relative URL patterns that might trigger similar parsing vulnerabilities. The vulnerability's resolution demonstrates the importance of rigorous input validation in URL parsing libraries and highlights the critical need for thorough testing of edge cases in web browser security implementations. Organizations should also monitor for similar vulnerabilities in other browser components and maintain updated threat intelligence feeds to identify potential related exploits that might leverage similar parsing weaknesses in web infrastructure components.