CVE-2019-11751 in Firefox
Summary
by MITRE
Logging-related command line parameters are not properly sanitized when Firefox is launched by another program, such as when a user clicks on malicious links in a chat application. This can be used to write a log file to an arbitrary location such as the Windows 'Startup' folder. <br>*Note: this issue only affects Firefox on Windows operating systems.*. This vulnerability affects Firefox < 69 and Firefox ESR < 68.1.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 09/11/2020
This vulnerability represents a critical security flaw in Mozilla Firefox's handling of command line parameters on Windows systems, specifically impacting versions prior to 69 and Firefox ESR versions prior to 68.1. The issue stems from inadequate input sanitization when Firefox processes logging-related command line arguments that are passed to it by external programs or applications. When users interact with malicious content through chat applications or other third-party software, these applications can launch Firefox with specially crafted command line parameters that include logging directives. The vulnerability is particularly dangerous because it allows attackers to manipulate the logging behavior of Firefox in ways that can lead to persistent malware installation.
The technical flaw manifests when Firefox receives command line arguments containing logging parameters without proper validation or sanitization. On Windows systems, this allows attackers to specify arbitrary file paths for log file creation, potentially targeting sensitive directories such as the Windows Startup folder. This occurs because the application fails to properly validate or sanitize the path components of logging parameters, enabling path traversal attacks and arbitrary file system access. The vulnerability is categorized as a command injection issue where external input influences the logging behavior of the application, creating opportunities for malicious file placement and execution persistence. This flaw directly relates to CWE-77 and CWE-20, which address command injection vulnerabilities and input validation issues respectively.
The operational impact of this vulnerability is significant for Windows users of affected Firefox versions, as it enables attackers to achieve persistent execution through legitimate browser processes. When users click on malicious links in chat applications, the external program can launch Firefox with crafted logging parameters that write log files to predetermined locations within the Windows file system. This capability allows threat actors to place malicious executables in startup folders or other persistent locations, ensuring that malware executes automatically with each system boot. The vulnerability effectively bypasses traditional security measures by leveraging Firefox's legitimate logging functionality to establish persistence, making it particularly insidious for users who may not suspect their browser interactions with chat applications.
Mitigation strategies for this vulnerability require immediate patching of affected Firefox installations to versions 69 or later, or Firefox ESR 68.1 and newer. System administrators should implement application whitelisting policies that restrict execution of unsigned binaries from startup folders and other sensitive locations. Network administrators should monitor for unusual logging activities or file creation patterns in Windows systems, particularly in startup directories. Users should exercise caution when interacting with chat applications or other third-party software that may launch Firefox, as these applications could potentially exploit the vulnerability. The ATT&CK framework categorizes this issue under T1059.001 for command and scripting interpreter, and T1068 for exploit for privilege escalation through application misconfiguration, highlighting the need for comprehensive endpoint protection and user awareness training. Organizations should also implement regular security assessments to identify and remediate similar input validation vulnerabilities in other browser applications and system components.