CVE-2018-5128 in Firefox
Summary
by MITRE
A use-after-free vulnerability can occur when manipulating elements, events, and selection ranges during editor operations. This results in a potentially exploitable crash. This vulnerability affects Firefox < 59.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 02/17/2020
The vulnerability identified as CVE-2018-5128 represents a critical use-after-free flaw within the Firefox browser's rendering engine that specifically impacts how the application handles editor operations involving elements, events, and selection ranges. This type of vulnerability occurs when a program continues to reference memory that has already been freed, creating potential pathways for malicious exploitation. The issue manifests during the manipulation of rich text editing components where Firefox's internal structures for managing document elements and user interactions become corrupted through improper memory management practices. The vulnerability is particularly concerning because it affects the core editing functionality of the browser, which is frequently utilized by users during web browsing activities.
The technical implementation of this vulnerability stems from improper handling of memory references within Firefox's DOM (Document Object Model) manipulation code. When users interact with editable content areas or perform operations involving text selection and element manipulation, the browser's internal memory management system fails to properly track object lifecycles, leading to scenarios where freed memory locations are accessed again. This memory corruption can be triggered through carefully crafted web content that leverages JavaScript APIs related to selection ranges and element manipulation. The flaw typically occurs in the gecko rendering engine's handling of editor commands, where objects representing selection ranges and document elements are not properly invalidated or reinitialized after their associated memory has been released.
The operational impact of CVE-2018-5128 extends beyond simple browser crashes to potentially enable remote code execution attacks. An attacker could craft malicious web pages that, when loaded in Firefox, trigger the use-after-free condition and subsequently execute arbitrary code with the privileges of the browser process. This vulnerability aligns with CWE-416, which specifically addresses use-after-free conditions in software development, and represents a prime example of how browser-based memory corruption vulnerabilities can be exploited for privilege escalation. The attack surface is particularly broad since editing operations are common across web applications, making this vulnerability potentially exploitable in numerous real-world scenarios. The vulnerability affects all versions of Firefox prior to 59, representing a significant security gap that could be exploited by attackers targeting users with outdated browser versions.
Organizations and users should prioritize immediate remediation by upgrading to Firefox version 59 or later, which contains patches addressing the memory management issues in the editor component. Security teams should implement monitoring for exploitation attempts targeting this vulnerability, particularly in environments where users may be running outdated browser versions. The mitigation strategy should also include user education regarding the importance of keeping browser software updated and the risks associated with visiting untrusted websites that may contain malicious content designed to exploit such vulnerabilities. Additionally, implementing browser security features such as sandboxing and content security policies can provide additional defense-in-depth measures against exploitation attempts targeting this specific memory corruption flaw.