CVE-2018-5113 in Firefox
Summary
by MITRE
The "browser.identity.launchWebAuthFlow" function of WebExtensions is only allowed to load content over "https:" but this requirement was not properly enforced. This can potentially allow privileged pages to be loaded by the extension. This vulnerability affects Firefox < 58.
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Analysis
by VulDB Data Team • 07/20/2024
The vulnerability identified as CVE-2018-5113 resides within the Firefox browser's WebExtensions API implementation, specifically targeting the browseridentitylaunchWebAuthFlow function. This function serves as a critical component for authentication flows within browser extensions, enabling extensions to initiate web-based authentication processes through the browser's built-in identity management system. The flaw represents a significant security regression that undermines the fundamental security model designed to protect users from malicious content injection during authentication processes. The vulnerability affects Firefox versions prior to 58, indicating a prolonged window during which the flaw remained unaddressed and potentially exploitable by threat actors.
The technical nature of this vulnerability stems from improper enforcement of security protocols within the WebExtensions framework. While the function was designed to strictly require HTTPS connections for loading content, the validation mechanism failed to properly enforce this requirement. This allows malicious extensions to potentially load content over insecure HTTP connections, bypassing the intended security boundary that should prevent untrusted content from being loaded in privileged contexts. The flaw essentially creates a pathway for extensions to load content that should be restricted to secure connections, thereby undermining the isolation between different security contexts within the browser's extension environment. This represents a direct violation of the principle of least privilege and secure communication practices that should govern all browser extension interactions.
The operational impact of CVE-2018-5113 extends beyond simple protocol enforcement failures, creating potential attack vectors that could be exploited by malicious actors. When extensions can bypass HTTPS requirements, they gain the ability to load content from untrusted sources that could perform man-in-the-middle attacks, inject malicious scripts, or redirect users to phishing sites. This vulnerability particularly affects the authentication flow process where users expect their credentials to be protected through secure channels. The implications are severe because authentication flows are often targeted by attackers seeking to capture user credentials or manipulate authentication processes. The vulnerability could enable attackers to craft malicious extensions that appear legitimate but can load insecure content during authentication, potentially leading to credential theft or session hijacking scenarios.
This vulnerability maps directly to CWE-310, which covers cryptographic issues related to insecure communications and improper enforcement of security protocols. The flaw also aligns with ATT&CK technique T1190, which addresses exploitation of vulnerabilities in web browsers and their extensions. The improper enforcement of HTTPS requirements creates a persistent security gap that could be leveraged for various attack vectors including credential harvesting, session manipulation, and privilege escalation within the browser environment. Security researchers and threat actors alike would recognize this as a critical flaw because it directly impacts the trust model between browser extensions and users, particularly during sensitive authentication operations.
Mitigation strategies for CVE-2018-5113 require immediate action to upgrade affected Firefox installations to version 58 or later where the vulnerability has been addressed. Organizations should implement comprehensive extension vetting processes that include security assessments of all installed browser extensions, particularly those that interact with authentication systems or handle sensitive user data. System administrators should consider implementing browser hardening policies that restrict extension installation and usage, while security teams should monitor for suspicious extension behavior that might indicate exploitation attempts. Additionally, users should be educated about the risks of installing extensions from untrusted sources and the importance of keeping browser software updated to address known vulnerabilities. The fix implemented in Firefox 58 likely involved strengthening the validation logic for the browseridentitylaunchWebAuthFlow function to properly enforce HTTPS requirements and prevent insecure content loading in privileged contexts.