Firefox no longer opens local htm help files
Hi, I use Firefox as my default browser and a while ago it stopped opening help files from a software package I use.
When I click the help button in the software the link in Firefox shows up as "file:///C:/Program%20Files%20(x86)/CST%20STUDIO%20SUITE%202019/Online%20Help/cst_studio_suite_help.htm" but Firefox doesn't open it - I either have to copy the link into another browser or navigate to the path shown and 'open with' another browser.
Is there an option in Firefox that will allow me to open these files? I've gone through quite a few settings but haven't had any luck so far. Any suggestions would be appreciated.
כל התגובות (2)
Hmm, maybe.
Firefox's security settings prohibit locally saved pages from free-ranging around your hard drive. That may not be needed for professionally developed help systems, but it's important for pages you save from the web.
Firefox 68 imposed a further restrictions to prevent exfiltration of valuable data within reach of a local page, as demonstrated in an available exploit. More info:
- https://developer.mozilla.org/docs/Web/HTTP/CORS/Errors/CORSRequestNotHttp
- https://www.mozilla.org/security/advisories/mfsa2019-21/#CVE-2019-11730
If your local help system uses scripts to change pages in frames, that would explain why it is affected. If it is unusable and critical to you, you could roll back the patch as follows:
(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button promising to be careful or accepting the risk.
(2) In the search box above the list, type or paste uniq and pause while the list is filtered
(3) Double-click the privacy.file_unique_origin preference to switch the value from true to false
Was that it?
To mitigate the vulnerability:
If you save pages from untrusted sites in a separate folder, e.g., Downloads\Untrusted, then it would be difficult for an attack page to find any valuable content using local file links.
That's great - I've followed that and the help files load now :D
I never save pages from the web but if if ever comes up in future I will save as you've suggested.
Thank you for the help, much appreciated :D