This Firefox STIG leaves out important details. They could make it very simple to implement but they don’t.  For more, see: http://kb.mozillazine.org/About:config

1) Create a file called local-settings.js and add one line:
pref(“general.config.filename”,”mozilla.cfg”);

2) Place local-settings.js in:

c:\<firefox path>\defaults\pref folder.

3) Create a file called mozilla.txt. Add the text below (everything under contents of mozilla.txt).  Launch Firefox and browse to:
http://www.alain.knaff.lu/howto/MozillaCustomization/cgi/byteshf.cgi

4) View the middle of the page. Under Upload mozilla.txt to get mozilla.cfg (byteshift 13), click browse, select your mozilla.txt file. Next, click Convert mozilla.txt to mozilla.cfg, save the file when prompted and place it in c:\<firefox path>\Mozilla Firefox\.

Contents of mozilla.txt:

//Firefox Settings
lockPref(“security.tls.version.min”, 1);
lockPref(“security.default_personal_cert”, “Ask Every Time”);
lockPref(“network.protocol-handler.external.shell”, false);
lockPref(“plugin.disable_full_page_plugin_for_types”, “application/pdf,application/fdf,application/xfdf,application/lsl,application/lso,application/lss,application/iqy,application/rqy,application/xlk,application/xls,application/xlt,application/pot,application/pps,application/ppt,application/dos,application/dot,application/wks,application/bat,application/ps,application/eps,application/wch,application/wcm,application/wb1,application/wb3,application/rtf,application/doc,application/mdb,application/mde,application/ad,application/,application/adp”);
lockPref(“browser.formfill.enable”, false);
lockPref(“signon.autofillForms”, false);
lockPref(“signon.rememberSignons”, false);
lockPref(“privacy.sanitize.sanitizeOnShutdown”, true);
lockPref(“dom.disable_window_open_feature.status”, true);
lockPref(“dom.disable_window_move_resize”, true);
lockPref(“security.tls.version.max”, 3);
lockPref(“dom.disable_window_flip”, true);
lockPref(“dom.event.contextmenu.enabled”, false);
lockPref(“dom.disable_window_status_change”, true);
lockPref(“dom.disable_window_open_feature.status”, true);
lockPref(“browser.startup.homepage”, “about:home”);
lockPref(“app.update.enabled”, false);
lockPref(“extensions.update.enabled”, false);
lockPref(“browser.search.update”, false);
// The end