CVE-2020-6828 in Firefox ESR
Summary
by MITRE
A malicious Android application could craft an Intent that would have been processed by Firefox for Android and potentially result in a file overwrite in the user's profile directory. One exploitation vector for this would be to supply a user.js file providing arbitrary malicious preference values. Control of arbitrary preferences can lead to sufficient compromise such that it is generally equivalent to arbitrary code execution.<br> *Note: This issue only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox ESR < 68.7.
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Analysis
by VulDB Data Team • 06/03/2024
This vulnerability represents a critical privilege escalation flaw in Firefox for Android that stems from improper intent handling within the application's architecture. The vulnerability manifests when a malicious Android application crafts a specially crafted Intent that Firefox for Android processes, leading to potential file overwrite operations in the user's profile directory. The issue specifically affects Firefox ESR versions prior to 68.7 and is confined exclusively to the Android platform, leaving other operating systems unaffected. The core technical flaw lies in Firefox for Android's insufficient validation of incoming intents, particularly those that might contain file paths or configuration directives that could be interpreted as commands for profile modification.
The operational impact of this vulnerability extends far beyond simple file overwrites, as demonstrated by the exploitation vector involving user.js files that can provide arbitrary malicious preference values. When a malicious application successfully crafts an intent that triggers this vulnerability, it can effectively control arbitrary preferences within Firefox's configuration system. This level of control over browser preferences creates a pathway to complete system compromise, as arbitrary preference manipulation can enable attackers to modify critical browser behavior, inject malicious code, or alter security settings. The equivalence to arbitrary code execution stems from the fact that Firefox's preference system directly influences how the browser operates internally, including network handling, security policies, and plugin behavior. This vulnerability essentially allows an attacker to subvert Firefox's core operational parameters, effectively giving them complete control over the browser's execution environment.
The exploitation landscape for this vulnerability is particularly concerning given the widespread use of Firefox for Android and the ease with which malicious applications can craft such intents through Android's inter-application communication mechanisms. The vulnerability aligns with CWE-20, "Improper Input Validation," and specifically relates to CWE-78, "Improper Neutralization of Special Elements used in OS Command Injection," as the intent processing could potentially be manipulated to execute arbitrary commands or modify critical system files. From an ATT&CK perspective, this vulnerability maps to T1059.007, "Command and Scripting Interpreter: Python," and T1106, "Execution: System Script", as successful exploitation could enable command execution within the browser's context. The attack surface is further expanded by the fact that this vulnerability can be triggered through seemingly benign application interactions, making it particularly dangerous for users who may inadvertently interact with malicious applications.
Mitigation strategies for this vulnerability should focus on immediate version updates to Firefox ESR 68.7 or later, which contain the necessary patches to address the intent processing flaws. Organizations should also implement mobile application whitelisting policies to prevent the installation of untrusted applications that could potentially exploit this vulnerability. Network-level monitoring should be enhanced to detect suspicious intent traffic patterns, particularly those involving file operations in browser profile directories. Additionally, security awareness training should emphasize the importance of only installing applications from trusted sources, as the vulnerability relies heavily on user interaction with malicious applications. System administrators should also consider implementing application sandboxing measures to limit the potential impact of successful exploitation attempts. The vulnerability serves as a reminder of the critical importance of proper intent validation in mobile applications, particularly those that handle sensitive user data or system configuration parameters.