CVE-2017-5409 in Firefox
Summary
by MITRE
The Mozilla Windows updater can be called by a non-privileged user to delete an arbitrary local file by passing a special path to the callback parameter through the Mozilla Maintenance Service, which has privileged access. Note: This attack requires local system access and only affects Windows. Other operating systems are not affected. This vulnerability affects Firefox ESR < 45.8 and Firefox < 52.
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Analysis
by VulDB Data Team • 11/26/2025
The vulnerability identified as CVE-2017-5409 represents a critical privilege escalation flaw within the Mozilla Windows updater mechanism that leverages the Mozilla Maintenance Service to execute arbitrary file deletion operations. This vulnerability specifically targets the Windows operating system and exploits a design flaw in how the maintenance service handles callback parameters, allowing unprivileged users to manipulate the updater process into performing destructive actions on the local filesystem. The attack vector requires local system access but demonstrates a significant security weakness in the software update infrastructure that could be exploited by malicious actors with physical or remote access to vulnerable systems. The vulnerability affects Mozilla Firefox ESR versions prior to 45.8 and standard Firefox versions prior to 52, indicating this was a long-standing issue that required substantial version updates to address properly.
The technical exploitation of this vulnerability occurs through manipulation of the callback parameter within the Mozilla Maintenance Service, which operates with elevated privileges due to its role in system maintenance operations. When a non-privileged user invokes the updater with a specially crafted path in the callback parameter, the service executes with administrative rights and processes the malicious file path, resulting in the deletion of arbitrary local files. This represents a classic privilege escalation attack where user-level processes gain elevated system privileges through improper input validation and handling within the maintenance service. The flaw essentially allows a malicious user to bypass normal access controls and execute destructive operations that should normally require administrative privileges, making it particularly dangerous in environments where users may have local access but should not possess the ability to delete critical system files.
The operational impact of CVE-2017-5409 extends beyond simple file deletion capabilities and represents a fundamental breach in the security model of the Firefox update infrastructure. An attacker could potentially target critical system files, configuration data, or user documents, leading to system instability, data loss, or complete system compromise. The vulnerability's impact is particularly severe because it affects the update mechanism itself, potentially allowing attackers to prevent legitimate updates from occurring or to delete files necessary for the proper functioning of the browser or operating system. This attack requires only local system access, meaning that even in environments where network-level security is robust, a compromised local account could still be leveraged to cause significant damage. The vulnerability also demonstrates poor input sanitization practices within the maintenance service, which should never trust user-provided parameters without proper validation and privilege separation.
Mitigation strategies for CVE-2017-5409 primarily involve immediate software updates to versions that address the privilege escalation flaw, specifically Firefox ESR 45.8 and Firefox 52 or later. Organizations should implement comprehensive patch management procedures to ensure all affected systems receive updates promptly, as this vulnerability could be exploited by attackers with local access to cause significant operational disruption. System administrators should also consider implementing additional security controls such as restricting local user access where possible, monitoring for unusual file deletion patterns, and ensuring that the Mozilla Maintenance Service operates with the minimum necessary privileges. From a compliance perspective, this vulnerability aligns with CWE-276, which addresses improper privileges, and can be mapped to ATT&CK technique T1068, which covers local privilege escalation. The vulnerability also demonstrates the importance of proper privilege separation in system services and highlights the need for robust input validation in all components that handle user-supplied data, particularly those with elevated system access rights.