Author Topic: What is Avast Emergency Updater and why is it in my scheduled tasks?  (Read 96129 times)

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The Kitchen Sink

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Re: What is Avast Emergency Updater and why is it in my scheduled tasks?
« Reply #90 on: July 10, 2012, 07:09:16 PM »
Uh... no.
That hypothetical fix certainly wouldn't reboot your machine out of the blue, without asking... that would be harsh indeed.

As for deleting the executable - I'm just saying the by disabling the scheduled task you achieve exactly the same, but the solution is a bit more permanent (generally, if you delete an avast file, the installer notices that under specific circumstances and puts the file back).

That is a relief. I think many of us were under the impression it would automatically download/restart and be like....OMG!!?? 0_0

Thank you for your patience and your time.

PS- Low priority off switch would be nice as an option for a future update. Yes, I know it is small. Hence Low priority =D
(suggestion for the beta?)

Offline Skakara

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Re: What is Avast Emergency Updater and why is it in my scheduled tasks?
« Reply #91 on: July 18, 2012, 12:28:31 AM »
As for deleting the executable - I'm just saying the by disabling the scheduled task you achieve exactly the same, but the solution is a bit more permanent (generally, if you delete an avast file, the installer notices that under specific circumstances and puts the file back).
Disabling scheduled task, a permanent solution?

On my desktop PC:
- First I deleted the "avast! Emergency Update" task from Scheduled Tasks.
- Then ran program update (which doesn't find anything, which is normal since I've the latest version already), but which runs "AvastEmUpdate.exe" and it reinstalls the "avast! Emergency Update" task!!!

- I tried to disable the "avast! Emergency Update" task from Scheduled Tasks.
- Then ran program update (which doesn't find anything, which is normal since I've the latest version already), but which runs "AvastEmUpdate.exe" and it again reinstalls enables the "avast! Emergency Update" task!!!

Same thing happens on my laptop PC, except that I've to disable or delete the task from CCleaner (for some odd reason the Scheduled Tasks folder is empty! (logged in as an administrator!) I guess there's a bug too in the installer... which doesn't suprise me, the finished installation, when trying to register avast, shows an error message (red cross icon or something like that), but the message says something like: "successfully registered"... and after that, going to the "registration" window, it show 0 days.. after boot it says 30 days, so the registration right after installation FAILS totally... CHECK THIS NEW TOPIC FOR THIS PROBLEM EXACTLY)

So, how do I really PERMANENTLY disable the emergency updater?!

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Desktop PC: Windows XP SP3. Has been running from at least avast 4.x version. Customized settings. Shields installed & On: Network, Script & Behavior. Shield installed & Off: File (has been too buggy and slow to turn on on this machine, started from the first 5.x version, similar settings in 4.x worked just fine.). On-demand scans used for new files (+VirusTotal online scanner for files from unknown/shady sources), and saved custom full scan every month.. no malware.. if one knows what to do, it's possible to run a PC without "full" AV protection for better performance.

Laptop: Windows XP SP3. Clean new installation of 7.0.1456. No settings changed. Shields installed & On: File, Network, Script & Behavior.
« Last Edit: July 27, 2012, 11:40:56 PM by Skakara »

Offline Skakara

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Re: What is Avast Emergency Updater and why is it in my scheduled tasks?
« Reply #92 on: July 27, 2012, 11:39:15 PM »
Ok, about 10 days and not a single answer!? Would it be possible for avast team to respond to this concern?

Offline igor

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Re: What is Avast Emergency Updater and why is it in my scheduled tasks?
« Reply #93 on: July 27, 2012, 11:55:18 PM »
Yes, if you manually invoke a program update, the updater will probably gets re-registered - that's how it is.
The emergency updater is simply an integral part of avast, and there's no way to disable it that would "survive" things like "Repair" function or a manual program update [check].
« Last Edit: July 27, 2012, 11:58:59 PM by igor »

Offline Skakara

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Re: What is Avast Emergency Updater and why is it in my scheduled tasks?
« Reply #94 on: July 28, 2012, 12:17:56 AM »
"Probably gets re-registered"? Probably? You don't know for sure? Amazing.

So, that's how it is, let me get this straight:

1) When you keep avast on auto-update for program updates, then the emergency updater does NOT get enabled if it's disabled one way or other.* Yes/no?

2) When I do my avast program updates when I want them to happen (notify only, and invoking manual update when I'm ready), then emergency updater gets enabled if it's disabled. Yes/no?

I don't see the point/logic. Why?

*Couple of weeks ago you said: "disabling the scheduled task you achieve exactly the same, but the solution is a bit more permanent". I'm guessing that you meant when program updates is on auto because now you replied about manual program updates. Or does "a bit more permanent" only mean that it "probably gets re-registered"? (in that case it's only very very little "more permanent") My head spins. ;)

Offline igor

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Re: What is Avast Emergency Updater and why is it in my scheduled tasks?
« Reply #95 on: July 28, 2012, 01:03:59 AM »
The program is rather huge and complex, I won't pretend I know every tiny detail - if it offends you, sorry, but I'm not gonna study the huge installer source code because of that.
There is no ordinary option to disable the updater - so we're talking about damaging the program here to achieve that; hardly a normal scenario.

I know there are some self-checks (and subsequent self-repairs, if anything is found missing) performed under some circumstances, but no, I don't know what exactly those circumstances are; manually invoking a program update is one of them. The self-check will definitely restore a missing file, and as you've found out, it will also put back a missing registry key (which I didn't expect initially, that's why I wrote it's a more permanent solution - so I was wrong, it's basically an equal "solution").

Anyway, to sum things up, there is no reliable way to damage the program in such a way that the emergency updater gets disabled (yet other things work).
« Last Edit: July 28, 2012, 01:10:54 AM by igor »

Dch48

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Re: What is Avast Emergency Updater and why is it in my scheduled tasks?
« Reply #96 on: July 28, 2012, 03:00:29 AM »
The bottom line is, to me anyway, that the emergency updater is a good thing that will only come into play in very rare instances. It should be left alone and allowed to function. There is absolutely no reason to be concerned or worried about it's presence.

Offline Skakara

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Re: What is Avast Emergency Updater and why is it in my scheduled tasks?
« Reply #97 on: July 28, 2012, 01:01:16 PM »
The program is rather huge and complex, I won't pretend I know every tiny detail - if it offends you, sorry, but I'm not gonna study the huge installer source code because of that.
It doesn't offend me. It amazes me. And your further writing about this subject reveals even more things that amazes me. Between the lines you're telling us that avast doesn't document product development. Do you do any requirements specification and design documents before coding? The functionality of the emergency update should be documented as should be the rest of the program. Are you really telling us that your "documentation" is the source code? Amazing.

The self-check will definitely restore a missing file, and as you've found out, it will also put back a missing registry key
What registry key? At least on WinXP, AFAIK, there's only a file in the windows\tasks\ folder which contains all the settings of the scheduled task.

Anyway, to sum things up, there is no reliable way to damage the program in such a way that the emergency updater gets disabled (yet other things work).
When a program uses a 3rd party scheduler, which the Windows Scheduler is, and not an embedded scheduler (without settings), it's giving users a possibility to change that scheduled task... I would not call that "damaging the program", a bit far fetched IMO.


emergency updater is a good thing that will only come into play in very rare instances.
Hmm, scheduled to run every 12 hours AND at user logon. Rarely? I personally want to know everything that happens on my rig. It's raising questions in my mind if *any company name* is reluctant to tell about the behavior of the feature OR doesn't know how it actually functions.


Anyways, my testing shows that you can't 1) delete 2) disable 3) change task settings of the emergency update. It's always reinstated back to how avast wants it to be. You can stop it by using an "application behavior blocking" software (my Sunbelt Personal Firewall has that) OR you can disable the Windows Task Scheduler (which I will do.. I'm already using a much much better task schduler (+using less memory), nnCron Lite (it has "missed tasks" feature, which Windows XP doesn't have)).

Thank you for your replies.

Offline igor

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Re: What is Avast Emergency Updater and why is it in my scheduled tasks?
« Reply #98 on: July 28, 2012, 01:23:52 PM »
You're mixing unrelated things - this is not about the emergency updater itself (which could hardly re-register itself if unregistered, right?) - but rather about the ordinary updater, which tries to repair the installation. From its point of view, missing registration is a damage to the program, the same as missing a file. (And yes, the task are stored in the Tasks folder - though as far as I know, every task is also accompanied by a registry key - but the installer doesn't access the files directly, it uses the ordinary Scheduler API).

Again, I repeat that there is no supported way to disable the emergency updater. So whatever I was suggesting, was more in the area of "hacks" to bypass the ordinary functionality. So no, I don't think those ways are documented (though I certainly don't work on the installer part, so I'm guessing in some areas.)


The functionality of the emergency updater has been described here - it just makes a request to our server, to see if any fix is available. If so, it downloads it, verifies it and applies it; that's all it does.
And again, you can disable the task scheduler if you like, it won't affect the avast's functionality in any way - unless something really bad occurs, which of course we hope never happens.
« Last Edit: July 28, 2012, 01:38:06 PM by igor »

Offline Skakara

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Re: What is Avast Emergency Updater and why is it in my scheduled tasks?
« Reply #99 on: July 28, 2012, 03:38:03 PM »
... re-register ... unregistered ... missing registration ... the task are stored in the Tasks folder - though as far as I know, every task is also accompanied by a registry key
Is your multiple "register" words pointing to "windows registry" like in the last snippet (="registry key")? There's no info about individual tasks in the windows registry.. everything is in the task .job file. So I would again refrain from using terms like "damage to the program" because there are no "missing registration".

Again, I repeat that there is no supported way to disable the emergency updater. So whatever I was suggesting, was more in the area of "hacks" to bypass the ordinary functionality. So no, I don't think those ways are documented (though I certainly don't work on the installer part, so I'm guessing in some areas.)
I think that you're mixing things here. I was NOT talking about documenting "how to disable emergency updater", I was talking about documenting the program behavior in general.

I asked you in what conditions avast re-enables/instates the task, to which you replied that you don't know for sure and you won't start studying the source code. To which I replied asking you whether you have any documentation of the program or not. A design document (made BEFORE coding), if made correctly, should document how the program works, i.e. it would show, quoting myself, "in what conditions avast re-enables/instates the task".

I'm sorry that this got so convoluted. Hope this clears things up.

Offline igor

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Re: What is Avast Emergency Updater and why is it in my scheduled tasks?
« Reply #100 on: July 28, 2012, 04:27:56 PM »
By the word "register" (a opposed to "registry") I mean "register to be started" ("schedule", if you wish) - in any way the Scheduler actually implements that, registry, files, whatever.
And yes, there are registry keys associated with the tasks (though they might actually duplicate the info stored in the job file). They contain hashes of the the job files, and the job files are verified against those hashes when started. That's why the Stuxnet malware had to perform the collision attack (CRC32, wasn't that hard) to change the content of the files, and that's why it was subsequently changed to SHA-256.


Some things are documented more, some less - especially the parts that were created over 10 years ago probably have some gaps (yes, installer might be one of those, but it's being worked on). But as I said, I don't develop the installer part (which is a bit of a separate project) and I'm not familiar either with its code or its documentation. Anyway, I was just trying to give some info based on my past experience; if I had to spend time on checking the code or documentation to give the answer, honestly, I wouldn't.
« Last Edit: July 28, 2012, 04:31:34 PM by igor »

Offline Skakara

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Re: What is Avast Emergency Updater and why is it in my scheduled tasks?
« Reply #101 on: July 28, 2012, 04:44:40 PM »
there are registry keys associated with the tasks (though they might actually duplicate the info stored in the job file).
Show me. Tell me the full path in WinXP registry where I can find the emergency update scheduled task. Thank you.

Edit: I took the SHA-256 hash of the task file and searched my registry with it, nothing came up.

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This is to all; if you're wondering why you're not seeing the "avast! Emergency Update" task in "Scheduled Tasks" folder, when some users report that they see it. It's a hidden task and some users might have a registry key (put by some other software) that makes it visible even if it's hidden. Notice that setting "show hidden files and folders" from explorer "folder options -> view" does NOT show hidden task files! Here's the registry key if you like to see hidden tasks in Scheduled Tasks folder (reboot needed):

Code: [Select]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SchedulingAgent]
"ViewHiddenTasks"=dword:00000001
« Last Edit: July 28, 2012, 05:41:07 PM by Skakara »

Offline igor

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Re: What is Avast Emergency Updater and why is it in my scheduled tasks?
« Reply #102 on: July 28, 2012, 07:38:27 PM »
OK, not on XP.
Starting with Vista, it's in HKLM\Software\Microsoft\Windows NT\CurrentVersion\Schedule\TaskCache\Tasks.

Offline Skakara

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Re: What is Avast Emergency Updater and why is it in my scheduled tasks?
« Reply #103 on: July 28, 2012, 10:55:37 PM »
Thanks Igor. Good to know. (I'm a developer myself and also always interested to learn more.) :)

norel

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Re: What is Avast Emergency Updater and why is it in my scheduled tasks?
« Reply #104 on: July 29, 2012, 06:12:13 AM »
The easiest way I know of is to disable it with a firewall. It stays disabled, but if you reinstall or repair it might reactivate. Just disable it again.