CVE-2015-1298 in Chrome
Summary
by MITRE
The RuntimeEventRouter::OnExtensionUninstalled function in extensions/browser/api/runtime/runtime_api.cc in Google Chrome before 45.0.2454.85 does not ensure that the setUninstallURL preference corresponds to the URL of a web site, which allows user-assisted remote attackers to trigger access to an arbitrary URL via a crafted extension that is uninstalled.
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Analysis
by VulDB Data Team • 06/14/2022
The vulnerability described in CVE-2015-1298 represents a significant security flaw in Google Chrome's extension handling mechanism that could enable remote attackers to redirect users to arbitrary web destinations. This issue resides within the RuntimeEventRouter::OnExtensionUninstalled function located in extensions/browser/api/runtime/runtime_api.cc, which is part of Chrome's core extension API implementation. The flaw specifically affects Chrome versions prior to 45.0.2454.85, making it a critical concern for users running outdated browser versions.
The technical nature of this vulnerability stems from insufficient validation of the setUninstallURL preference during extension uninstallation processes. When a user uninstalls a Chrome extension, the browser typically triggers an uninstallation URL that may be specified by the extension developer. However, Chrome's implementation failed to properly verify that this URL belonged to a legitimate web site, allowing malicious extensions to specify arbitrary URLs that could be accessed during the uninstallation process. This validation gap creates an attack surface where attackers can craft malicious extensions that, when uninstalled, redirect users to phishing sites, malicious domains, or other harmful destinations.
The operational impact of this vulnerability extends beyond simple URL redirection, as it provides attackers with a user-assisted remote execution vector that can be leveraged for various malicious activities. Attackers can create seemingly legitimate extensions that appear harmless during installation but contain malicious uninstallation URLs designed to harvest user credentials, deliver malware, or perform other harmful actions. The user-assisted nature of this attack means that victims must actively uninstall the malicious extension for the exploit to be triggered, but this requirement does not significantly reduce the risk given that users often uninstall extensions for various reasons. This vulnerability directly relates to CWE-20, which describes improper input validation, and aligns with ATT&CK technique T1176 for "Browser Extensions) where adversaries leverage browser extension capabilities to execute malicious code or redirect users.
The security implications of this vulnerability are particularly concerning in enterprise environments where users may be less cautious about extension installation and uninstallation processes. Attackers can exploit this flaw by creating extensions that appear legitimate but contain malicious uninstallation URLs, potentially leading to credential theft, malware delivery, or other security breaches. Organizations should consider implementing browser extension policies that restrict the installation of extensions from untrusted sources and regularly audit installed extensions to identify potentially malicious ones. The vulnerability also highlights the importance of proper URL validation in browser security mechanisms, as the failure to validate uninstallation URLs represents a critical oversight in Chrome's extension security model that could be exploited in combination with other attack vectors.
Mitigation strategies for this vulnerability primarily involve upgrading to Chrome version 45.0.2454.85 or later, which includes the necessary fixes to properly validate uninstallation URLs. System administrators should also implement comprehensive browser security policies that restrict extension installation and monitor for suspicious extension behavior. Additionally, users should be educated about the risks of installing extensions from untrusted sources and the importance of carefully reviewing extension permissions before installation. The fix implemented by Google addresses the core validation issue by ensuring that uninstallation URLs are properly verified before execution, preventing malicious extensions from redirecting users to arbitrary destinations during the uninstallation process. This remediation aligns with industry best practices for input validation and helps prevent similar vulnerabilities from occurring in future browser implementations.