Firefox not configured to prompt user before download and opening for required file types.

From Mozilla Firefox Security Technical Implementation Guide

Part of DTBF110 - FireFox Preferences – Open Confirmation

Associated with: CCI-001243

SV-16711r2_rule Firefox not configured to prompt user before download and opening for required file types.

Vulnerability discussion

New file types cannot be added directly to the helper applications or plugins listing. Files with these extensions will not be allowed to use Firefox publicly available plugins and extensions to open. The application will be configured to open these files using external applications only. After a helper application or save to disk download action has been set, that action will be taken automatically for those types of files. When the user receives a dialog box asking if you want to save the file or open it with a specified application, this indicates that a plugin does not exist. The user has not previously selected a download action or helper application to automatically use for that type of file. When prompted, if the user checks the option to Do this automatically for files like this from now on, then an entry will appear for that type of file in the plugins listing and this file type is automatically opened in the future. This can be a security issue. New file types cannot be added directly to the Application plugin listing.

Check content

Open a browser window, type "about:config" in the address bar. Criteria: If the “plugin.disable_full_page_plugin_for_types” value is not set to include the following external extensions and not locked, then this is a finding: PDF, FDF, XFDF, LSL, LSO, LSS, IQY, RQY, XLK, XLS, XLT, POT PPS, PPT, DOS, DOT, WKS, BAT, PS, EPS, WCH, WCM, WB1, WB3, RTF, DOC, MDB, MDE, WBK, WB1, WCH, WCM, AD, ADP.

Fix text

Ensure the following extensions are not automatically opened by Firefox without user confirmation. Do not use plugins and add-ons to open these files. Use the "plugin.disable_full_page_plugin_for_types" preference to set and lock the following extensions so that an external application rather than an add-on or plugin will not be used. (PDF, FDF, XFDF, LSL, LSO, LSS, IQY, RQY, XLK, XLS, XLT, POT PPS, PPT, DOS, DOT, WKS, BAT, PS, EPS, WCH, WCM, WB1, WB3, RTF, DOC, MDB, MDE, WBK, WB1, WCH, WCM, AD, ADP)

Pro Tips

Lavender hyperlinks in small type off to the right (of CSS class id, if you view the page source) point to globally unique URIs for each document and item. Copy the link location and paste anywhere you need to talk unambiguously about these things.

You can obtain data about documents and items in other formats. Simply provide an HTTP header Accept: text/turtle or Accept: application/rdf+xml.

Powered by sagemincer