CVE-2016-1948 in Firefox
Summary
by MITRE
Mozilla Firefox before 44.0 on Android does not ensure that HTTPS is used for a lightweight-theme installation, which allows man-in-the-middle attackers to replace a theme s images and colors by modifying the client-server data stream.
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Analysis
by VulDB Data Team • 07/06/2022
The vulnerability identified as CVE-2016-1948 represents a critical security flaw in Mozilla Firefox versions prior to 44.0 on Android platforms. This issue stems from the browser's failure to enforce secure HTTPS connections during the installation of lightweight themes, creating a significant attack vector for man-in-the-middle adversaries. The flaw specifically affects the theme installation process where Firefox should have verified the integrity of theme components through encrypted channels but instead allowed unencrypted HTTP transfers to proceed.
The technical implementation of this vulnerability resides in the browser's protocol handling for lightweight theme installations. When users attempt to install custom themes through the Firefox interface, the application should establish a secure HTTPS connection to download theme resources including images and color schemes. However, Firefox 43.0 and earlier versions would proceed with HTTP connections even when the target server supported HTTPS, thereby exposing the theme installation process to interception and modification by attackers positioned between the client and server.
This vulnerability directly impacts the principle of secure communications and can be categorized under CWE-319, which addresses the exposure of sensitive information through improper use of encryption. The operational impact of this flaw extends beyond simple theme manipulation as it demonstrates a fundamental breakdown in Firefox's security model for handling user-customizable content. Attackers could substitute malicious images, modify color schemes, or inject harmful code through the compromised theme installation process, potentially leading to more severe security consequences including credential theft or system compromise.
From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1190, which involves exploiting vulnerabilities in web applications to conduct man-in-the-middle attacks. The attack surface is particularly concerning given that lightweight themes are commonly used and trusted components of the browser interface, making them attractive targets for attackers seeking to establish persistent footholds or conduct surveillance operations. The vulnerability affects not only individual users but also organizations that rely on Firefox for business operations, as compromised themes could serve as entry points for broader network infiltration.
The mitigation strategy for this vulnerability requires immediate patching of affected Firefox versions to 44.0 or later, which implements proper HTTPS enforcement during theme installations. Additionally, security-conscious organizations should implement network monitoring to detect unusual traffic patterns during theme installation processes and consider deploying network security solutions that can detect and prevent HTTP-to-HTTPS downgrade attacks. Users should be educated about the risks of installing third-party themes and the importance of verifying theme sources through official channels only. The vulnerability also underscores the importance of maintaining up-to-date software and implementing proper security policies for browser usage in enterprise environments.