What would cause a .dmg file to pop up before a YouTube video?

[Mannheim62]

Yesterday, I was hosting a meeting of the photography club I belong to. I brought up a YouTube video on macro photography and before it began to play, the video screen on YouTube (not my iMac screen) turned black, the curser started to spin and for a split second a small window appeared and the only thing anyone (5 of us total) remembered seeing was “.dmg”. The window disappeared and the video began playing. I never got a pop up from macOS Mojave asking me if I wanted to install anything. I immediately closed Safari and ran Malwarebytes and it came back clean. Then I looked in my Applications Folder and I didn’t see anything out of the ordinary. I’ve never had this happen before. Is there anything else I can do to make sure my system is safe? If I were alone, I would have thought I was seeing things; but if 4 other people saw the same thing, I feel better knowing I’m not losing my mind. Any thoughts, ideas or suggestions would be greatly appreciated.

Thank You,
Mike

 

[Lifeisabeach]

Did you look in your Downloads folder? It sounds like a malicious attempt to trick you into installing some sort of malware. They'll try to "silently" push a DMG into your downloads folder for the user to find later and open up... sometimes wondering what it is, sometimes thinking it's legit due to how it's named. The DMG file, if it truly did get downloaded, won't cause any issues on it's own. You'd have to actively open and interact with its contents for anything to happen. Consider using a search tool like EasyFind to scan your computer for DMG files.

 

[Mannheim62]

Did you look in your Downloads folder? It sounds like a malicious attempt to trick you into installing some sort of malware. They'll try to "silently" push a DMG into your downloads folder for the user to find later and open up... sometimes wondering what it is, sometimes thinking it's legit due to how it's named. The DMG file, if it truly did get downloaded, won't cause any issues on it's own. You'd have to actively open and interact with its contents for anything to happen. Consider using a search tool like EasyFind to scan your computer for DMG files.

Thank you replying. Yes, I did look in my Downloads folder and it's empty. Sorry, I should have stated that in my OP. I'll take a look at EasyFind. I have the free version of Malwarebytes; would the paid version be a better choice because it's real time protection?

Mike

 

[pm-r]

I'll take a look at EasyFind. I have the free version of Malwarebytes; would the paid version be a better choice?

You might want to add Find Any File (FAF) to your application arsenal as well:
Thomas Tempelmann - Find Any File

The paid version of Malwarebytes just allows you to run it automatically in the background. Paid or free are both the same application but the free version you have to run manually after it's demo trial.



- Patrick
======

 

[Mannheim62]

You might want to add Find Any File (FAF) to your application arsenal as well:
Thomas Tempelmann - Find Any File

The paid version of Malwarebytes just allows you to run it automatically in the background. Paid or free are both the same application but the free version you have to run manually after it's demo trial.



- Patrick
======

Thanks for replying Patrick. I understand regarding Malwarebytes. I ran FAF and it revealed 9 items.


The first 3 files have to do with something called "iBridge1_1Customer.bundle", the next 5 files are related to my Canon imageClass MF424dw printer and the last file is self-explanatory.

Mike

 

[ferrarr]

You would need to post a screen shot of the - .dmg that pops up - before the youtube video?

 

[Mannheim62]

You would need to post a screen shot of the - .dmg that pops up - before the youtube video?

I wish I could have Bob, but is was only there for a split second.

Mike

 

[ferrarr]

Well, if a dmg loads, it will have an icon, either on your desktop, or in the sidebar. Do you see anything there? If it happens again, restart should get rid of it.

 

[Mannheim62]

Well, if a dmg loads, it will have an icon, either on your desktop, or in the sidebar. Do you see anything there? If it happens again, restart should get rid of it.

No icon on the desktop or sidebar; I checked that yesterday but should have included that in my OP. If it happens again I'll restart. Thank you.

 

[Slydude]

I wish I could have Bob, but is was only there for a split second.

Mike

Here's the only way I can think of to get a good look at something like that:
1. Launch Quicktime Player and choose New Screen Recording from the file menu.
2. Press the record button to start the recording.
3. Launch the video containing the offending icon. Once you think the icon has appeared on the screen you can stop the screen recording.
4. Now it should be possible to go through the video slowly until you reach a frame with the icon on it and take a screenshot.

Not sure is will work but it should.

 

[Mannheim62]

Very good idea, thank you so much !!!

 

[Lifeisabeach]

Look at the “Date Modified” column. There’s one for Toast dated August 3rd, 2019. Is that when this happened? If so, I’d wager that is the culprit. You can open it, but DO NOT interact with the contents... just have Malwarebytes scan it. Better yet, just trash it. No one uses that anymore and if I’m not mistaken, malware masquerading as Toast was one of the more common scenarios a while back. If you want to be more certain before trashing it, it may be helpful to know where it is on your Mac.

 

[Mannheim62]

Look at the “Date Modified” column. There’s one for Toast dated August 3rd, 2019. Is that when this happened? If so, I’d wager that is the culprit. You can open it, but DO NOT interact with the contents... just have Malwarebytes scan it. Better yet, just trash it. No one uses that anymore and if I’m not mistaken, malware masquerading as Toast was one of the more common scenarios a while back. If you want to be more certain before trashing it, it may be helpful to know where it is on your Mac.

Unfortunately no, it happened yesterday Aug. 6. Believe it or not, I still use Toast 12 and it works fine. Toast 17 is another story; that's why I went back to Toast 12. To my knowledge (and I use that term loosely) there's no way to scan an individual file on a Mac. If I'm mistaken please advise. I ran a Malwarebytes scan yesterday and again today and they both came back clean.

 

[Lifeisabeach]

Unfortunately no, it happened yesterday Aug. 6. Believe it or not, I still use Toast 12 and it works fine. Toast 17 is another story; that's why I went back to Toast 12. To my knowledge (and I use that term loosely) there's no way to scan an individual file on a Mac. If I'm mistaken please advise. I ran a Malwarebytes scan yesterday and again today and they both came back clean.

I’m not able to confirm right now, but it seems like MalwareBytes can be told to scan a specific volume, which can be a mounted DMG image. But otherwise yeah, I don’t think it can do an individual file. As for the actual DMG file, I supposed the modified date could still preceed the date it was downloaded. Also, unless you are keeping an archived copy of Toast handy, I don’t know why that DMG would exist in the first place. But then this is Toast we’re talking about here. /smirk.

 

[Mannheim62]

Thanks for the info on Malwarebytes. Not to get off topic but I actually did have an archived copy of Toast 12 and I'm glad I did. After I uninstalled the disaster they call Toast 17, I needed something to fall back on. I wish I could find another Toast option.

Mike

 

[dtravis7]

Thanks for the info on Malwarebytes. Not to get off topic but I actually did have an archived copy of Toast 12 and I'm glad I did. After I uninstalled the disaster they call Toast 17, I needed something to fall back on. I wish I could find another Toast option.

Mike

Just curious. I also got a newer Toast (15) and it had issues converting videos for burning. What issues did you have with 17?? I had to roll back to 11 myself.

It's sad there are no other options that do everything Toast does. On the Mac Toast is like Nero on the PC. I have not found anything so far that does all Toast does. Sad Roxio messed a few things up.

 

[Slydude]

If all you need is basic burning capability check out Burn. It doesn't have some of the fancy menus like Apple's iDVD program but can handle burning of basic discs for data, DVDs, CDs, etc.

 

[pm-r]

It's sad there are no other options that do everything Toast does. On the Mac Toast is like Nero on the PC. I have not found anything so far that does all Toast does. Sad Roxio messed a few things up.

Just for the record, Roxio Toast started to mess up their Toast application many versions ago, but then passed the job over to Corel Corporation to completely mess it up, which I believe is up to version 18 now.

And as Sly mentioned, the last time I needed any burning software I just used Burn.app that worked fine for me. I can't recall the last time I use my version of Toast at 12. But every version after their version 6 started going goofy as far as I'm concerned.



- Patrick
======

 

[dtravis7]

I know all about Corel. Actually there are 4 companies involved. When I got 15 and it messed up every video it converted for burning I demanded my $$$ back and had to talk to 4 different companies to get that $$$ which I finally got. Toast 11 works perfectly BTW. The only reason I upgraded to 15 over 11 was I was afraid with newer versions of Mac OS 11 would eventually no longer work. So far it does though.

I have recommended Burn to a few friends who do what I have to do to make a DVD for my customers and Burn messed things up that way. Burn is fine for basic burning but for what I do has issues. For just burning files to a DVD you can use Finder for that matter.

 

[Slydude]

@Dennis Don't want to take things too far astray here but what kinds of burns were being missed up? I don't burn many discs anymore but I like to keep on top of where potential problems are when recommending software.