Yet another JScript vulnerability

[woodyDa Boss]

Internet Explorer, the gift that keeps on giving. Looks like we have a brand new JScript bug. According to ADV200001: A remote code execution vulnerab
[See the full post at: Yet another JScript vulnerability]

4 users thanked author for this post.

jburk07, Fred, Nibbled To Death By Ducks, SueW

[abbodi86AskWoody_MVP]

Yes, let’s hope they don’t repeat September debacle 🙂

2 users thanked author for this post.

Nibbled To Death By Ducks, woody

[fernladyAskWoody Lounger]

I’m a home user with one windows7 computer and have Firefox 72.0.1 as my default browser, should I disable JScript in IE11?

Under Scripting there are 3 areas that are enabled, Active scripting, Enable XSS filter & Scripting of Java applets. Allow Programmatic clipboard access which is set to Prompt. Disable all???

Windows 7 Home Premium x64 AMD Group A Realtek PCLe GBE Family Controller

• This reply was modified 1 month ago by  fernlady.

[anonymous]

I would open Control Panel and go to Programs and Features. Then on the top left click on “Turn Windows Features on or off”.

Next find Internet Explorer 11 and uncheck the box.

I did this a couple of years ago and it hasn’t affected other programs or websites for me.

Consider using NoScript with Firefox and although there is a bit of a learning curve  any inconvenience will give you a more secure system as payback. Also HTTPS Everywhere is another secure option.

1 user thanked author for this post.

fernlady

[fernladyAskWoody Lounger]

That was easy. Thank you, so far no problems.

Windows 7 Home Premium x64 AMD Group A Realtek PCLe GBE Family Controller

[MoonbearAskWoody Lounger]

If you do ever need to re-enable Internet Explorer, It may not recreate the desktop icon when you do.

Just something to watch out for.

 

[MicrofixDa Boss]

Looks like MSFT has issued a temporary workaround for the IE vulnerability with instructions how to implement and undo for when a hot-fix-patch is released.

https://portal.msrc.microsoft.com/en-us/security-guidance/advisory/ADV200001

MSFT catalog patch for Windows 7 only? dunno, time will tell..

Win7 Pro x64 | Win8.1 Pro x64 | Linux Hybrids x86/x64 | Win7 Pro x86 | W10 never again

1 user thanked author for this post.

jburk07

[woodyDa Boss]

Yep, that’s the “Turn off JScript” fix I mentioned.

Nice of them to announce this on a Friday evening before a three-day (US) weekend…

1 user thanked author for this post.

jburk07

[anonymous]

As usual MS forgot to mention in the FAQ,  this temporary workaround also break Windows Media Player on Win 10. You’ll get a “Server execution failed error” when trying to play an MP4.

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jburk07, Microfix, woody

[EstherDAskWoody Plus]

It also causes “sfc” on Win7 to emit a cryptic error message, something about files it tried to restore but couldn’t, presumably because “sfc” also can no longer read the jscript.dll files after the workaround is implemented. Since the logfile generated by “sfc” is effectively unparsable by mere mortals, it is difficult to determine exactly what “sfc” is complaining about. Therefore, you may not want to implement this workaround if you rely on “sfc” to validate the health of your Win7 system.

3 users thanked author for this post.

jburk07, Microfix, woody

[MoonbearAskWoody Lounger]

If your not directly using Internet Explorer to access the internet, should this be worried about?

I have IE’s outbound connection blocked with Windows Firewall, should I also block the inbound connection as well?

[woodyDa Boss]

Not using IE is kind of a baseline security precaution.

I don’t know if you’re vulnerable outside of IE, but I would guess that if the exposure were really all that significant, we would have a patch by now.

4 users thanked author for this post.

jburk07, OscarCP, Moonbear, Fred

[MoonbearAskWoody Lounger]

In that case I’m leaving it alone, especially considering the issues being reported from using the workaround

[AmbularDAskWoody Plus]

Interesting.  I disabled jscript per the advisory, and Internet Explorer still worked fine (not that I use it much anymore,) but Firefox crashed at startup until I enabled it again.  Waterfox, Pale Moon, and IceDragon, however, did not seem to be affected.

Disabling jscript may also have broken Panda Dome, though I’m not sure about that, as this as a possible cause of the issues it was having did not occur to me until after I’d already given up in frustration and replaced it with Avast.

i7-4790k - Z97X-Gaming 3 - DDR3 2133 x 32GB - GTX 1070 FTW - Windows 7 Pro x64 SP1

4 users thanked author for this post.

jburk07, woody, Fred, samak

[Mitja KolsekAskWoody Plus]

We @0patch are planning to issue a micropatch for this next week which will prevent Internet Explorer from loading jscript.dll. This will not affect the permissions on jscript.dll and will likely keep the sfc command unaffected. It would be nice to learn from other users implementing Microsoft’s workaround what else that workaround breaks.

5 users thanked author for this post.

jburk07, Geo, Microfix, AmbularD, woody

[PKCanoDa Boss]

So far, the reports on side effects that have been reported on this site, as far as I know, are in the above posts.

1 user thanked author for this post.

woody

[Mitja Kolsek]

Our micropatches for CVE-2020-0674 are out, and an accompanying blog post: https://blog.0patch.com/2020/01/micropatching-workaround-for-cve-2020.html

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jburk07, Geo, Alex5723, Microfix

[GrargfarAskWoody Plus]

The workaround breaks printing to “Microsoft Print to PDF”. I had to revert it.

1 user thanked author for this post.

jburk07

[MrToad28AskWoody Lounger]

I use Win7 PC’s and never use IE..Use Firefox, Firefox variant Pale moon & Chrome. Would I be affected by this Jscript issue?

[Paul TAskWoody MVP]

Probably not, but it’s worth checking the browser web sites to see what they say about it.

cheers, Paul

[PKCanoDa Boss]

@Mitja-Kolsek

There are some other consequenses of the JavaScript bug posted here.

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