CVE-2017-7840 : What You Need to Know
Learn about CVE-2017-7840, a Firefox vulnerability allowing JavaScript injection in exported bookmarks, leading to social engineering and self-XSS attacks. Find mitigation steps and preventive measures.
A vulnerability in Firefox versions below 57 allows the injection of JavaScript into exported bookmarks, potentially leading to social engineering and self-cross-site-scripting attacks.
Understanding CVE-2017-7840
What is CVE-2017-7840?
The injection of JavaScript into an exported bookmarks file can occur when JavaScript code is inserted into user-provided tags within saved bookmarks. When the exported HTML file is subsequently accessed in a browser, the executed JavaScript comes into effect. This issue could potentially enable social engineering and self-cross-site-scripting (self-XSS) attacks, particularly if users are convinced to include malicious tags in their bookmarks, export them, and subsequently open the generated file.
The Impact of CVE-2017-7840
This vulnerability affects Firefox versions below 57, allowing malicious actors to execute JavaScript code through manipulated bookmarks, posing risks of social engineering and self-XSS attacks.
Technical Details of CVE-2017-7840
Vulnerability Description
JavaScript can be injected into an exported bookmarks file by placing JavaScript code into user-supplied tags in saved bookmarks. If the resulting exported HTML file is later opened in a browser, this JavaScript will be executed, potentially leading to social engineering and self-XSS attacks.
Affected Systems and Versions
- Product: Firefox
- Vendor: Mozilla
- Versions Affected: < 57
Exploitation Mechanism
The vulnerability arises from the failure to strip script elements from user-supplied tags in exported bookmarks, allowing the execution of JavaScript code.
Mitigation and Prevention
Immediate Steps to Take
- Update Firefox to version 57 or higher to mitigate the vulnerability.
- Avoid exporting bookmarks with user-supplied tags containing JavaScript code.
Long-Term Security Practices
- Educate users on safe bookmarking practices to prevent the inclusion of malicious tags.
- Regularly remind users to update their browsers to the latest versions for enhanced security.
Patching and Updates
- Stay informed about security advisories from Mozilla and promptly apply recommended patches and updates.