CVE-2018-5172 in Firefox
Summary
by MITRE
The Live Bookmarks page and the PDF viewer can run injected script content if a user pastes script from the clipboard into them while viewing RSS feeds or PDF files. This could allow a malicious site to socially engineer a user to copy and paste malicious script content that could then run with the context of either page but does not allow for privilege escalation. This vulnerability affects Firefox < 60.
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Analysis
by VulDB Data Team • 03/11/2023
The vulnerability identified as CVE-2018-5172 represents a significant security flaw in Mozilla Firefox browsers prior to version 60, specifically affecting the Live Bookmarks page and PDF viewer components. This issue stems from insufficient input validation and sanitization mechanisms within these browser features, creating an attack vector that leverages user interaction through clipboard manipulation. The vulnerability operates under the principle of cross-site scripting attacks where malicious content can be executed within the context of privileged browser pages, potentially compromising user security and privacy.
The technical implementation of this vulnerability occurs when users interact with RSS feed content or PDF documents within Firefox, particularly during copy-paste operations from the clipboard. The flaw allows for script injection when users paste content that contains malicious javascript code, which then executes within the security context of either the Live Bookmarks page or the PDF viewer. This behavior violates the fundamental security principle of sandboxing, where different browser components should operate in isolated environments to prevent cross-contamination of malicious code. The vulnerability specifically affects Firefox versions below 60, indicating that this was a known issue that required patching in the browser's security architecture.
The operational impact of CVE-2018-5172 extends beyond simple script execution, as it enables sophisticated social engineering campaigns where attackers can manipulate users into inadvertently executing malicious code. Attackers can craft content that appears legitimate within RSS feeds or PDF documents, then exploit the clipboard paste functionality to deliver payloads that execute with the privileges of the respective browser components. This vulnerability aligns with the CWE-79 classification for Cross-Site Scripting, specifically targeting the execution of untrusted code in web contexts. The attack vector demonstrates how user interaction can be weaponized to bypass traditional security controls, creating a pathway for persistent threats that can access session cookies, browser data, or perform actions on behalf of the user.
The implications of this vulnerability are particularly concerning within enterprise environments where users frequently interact with RSS feeds and PDF documents containing potentially malicious content. The lack of privilege escalation capabilities does not diminish the severity of the issue, as the executed scripts can still access sensitive browser functionality and potentially exfiltrate data. This vulnerability maps to ATT&CK technique T1059.007 for "Command and Scripting Interpreter: JavaScript" and T1566.001 for "Phishing: Spearphishing Attachment", demonstrating how the flaw can be exploited through both automated and social engineering approaches. Organizations should consider implementing additional security measures such as clipboard monitoring, enhanced input validation, and user education programs to mitigate the risk associated with this vulnerability. The fix implemented in Firefox 60 likely involved enhanced sanitization of clipboard content and stricter validation of input within the Live Bookmarks and PDF viewer components, aligning with security best practices for preventing injection attacks and maintaining secure browser functionality.