Chances of virus

boatcapt

macrumors member
Original poster
Dec 14, 2011
98
1
I recently have mailed quite a few packages via usps because of the holidays. I got a email saying a package wasn't delivered and it had a zip file and I tried to open it (stupid me), but nothing happened. So do you think I'm in the clear?
Thanks.
 
Nov 28, 2010
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Yep, as there are NO viruses for Mac OS X.
There are currently no viruses for Mac OS X in public circulation, only a handful of trojans and other malware, which have to be installed manually via entering the administrator password.
The only anti-virus you need to protect your Mac is education and common sense.
Also know, that the term "virus" is often used to refer to other kinds of malware, but there are differences, which you can find out by reading the following:

Mac Virus/Malware Info by GGJstudios

Maybe the .zip file was just empty?
 

GGJstudios

macrumors Westmere
May 16, 2008
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I recently have mailed quite a few packages via usps because of the holidays. I got a email saying a package wasn't delivered and it had a zip file and I tried to open it (stupid me), but nothing happened. So do you think I'm in the clear?
Thanks.
You don't need any 3rd party antivirus app to keep your Mac malware-free. Macs are not immune to malware, but no true viruses exist in the wild that can run on Mac OS X, and there never have been any since it was released 10 years ago. You cannot infect your Mac simply by visiting a website, unzipping a file, opening an email attachment or clicking on a web link. The only malware in the wild that can affect Mac OS X is a handful of trojans, which cannot infect your Mac unless you actively install them, and they can be easily avoided with some basic education, common sense and care in what software you install. Also, Mac OS X Snow Leopard and Lion have anti-malware protection built in, further reducing the need for 3rd party antivirus apps.
 

thatoneguy82

macrumors 68000
Jul 23, 2008
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About once a day or every couple of days my Sophos AV pops up to tell me that it has detected a virus or trojan horse. This is almost always when I get new spam mail. I use the "clean up" option and all is well.
 

GGJstudios

macrumors Westmere
May 16, 2008
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About once a day or every couple of days my Sophos AV pops up to tell me that it has detected a virus or trojan horse. This is almost always when I get new spam mail. I use the "clean up" option and all is well.
Sophos should be avoided, as it could actually increase your Mac's vulnerability, as described here and here... and here. I recommend you uninstall it. Any virus or trojan it's detecting is most likely Windows-based, which cannot affect your Mac.
 
Nov 28, 2010
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About once a day or every couple of days my Sophos AV pops up to tell me that it has detected a virus or trojan horse. This is almost always when I get new spam mail. I use the "clean up" option and all is well.
Even if Sophos has found something, it was most probably Windows malware, which can't affect Mac OS X. Be sure to read the Malware FAQ GGJstudios was kindly enough to compile and post.
 

thatoneguy82

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Jul 23, 2008
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Even if Sophos has found something, it was most probably Windows malware, which can't affect Mac OS X. Be sure to read the Malware FAQ GGJstudios was kindly enough to compile and post.
I'm good. I know enough regarding that. May not be an expert however. I was just simply sharing that malware are able to get in to macs and can be detected, even though they won't do any damage. But this in case if they forward these files or take out these files and put them on a PC.
 

thundersteele

macrumors 68030
Oct 19, 2011
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I recently have mailed quite a few packages via usps because of the holidays. I got a email saying a package wasn't delivered and it had a zip file and I tried to open it (stupid me), but nothing happened. So do you think I'm in the clear?
Thanks.
So, the email wasn't from USPS in the end? Or was it?

Opening an unknown attachment is always a bad idea, even if the chance to catch something on a Mac is vanishingly small.
 

GGJstudios

macrumors Westmere
May 16, 2008
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I'm good. I know enough regarding that. May not be an expert however. I was just simply sharing that malware are able to get in to macs and can be detected, even though they won't do any damage. But this in case if they forward these files or take out these files and put them on a PC.
If you want to scan for Windows malware without the increased vulnerability, ClamXav is a good choice, since it isn't a resource hog, detects both Mac and Windows malware and doesn't run with elevated privileges. You can run scans when you choose, rather than leaving it running all the time, slowing your system.
 

thatoneguy82

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Jul 23, 2008
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If you want to scan for Windows malware without the increased vulnerability, ClamXav is a good choice, since it isn't a resource hog, detects both Mac and Windows malware and doesn't run with elevated privileges. You can run scans when you choose, rather than leaving it running all the time, slowing your system.
Thanks for that app suggestion. Sophos was the only software I knew of. I really don't notice any lag in system performance or resources.
 

boatcapt

macrumors member
Original poster
Dec 14, 2011
98
1
It wasn't from USPS, they say they never send emails with attachments regarding your shipments.
 

ShoG

macrumors member
Dec 6, 2011
54
0
I wouldn't use ClamXav either, unless you want to see all your RAM get used up before your eyes.
 

GGJstudios

macrumors Westmere
May 16, 2008
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I wouldn't use ClamXav either, unless you want to see all your RAM get used up before your eyes.
Not true. ClamXav takes very little in the way of resources and RAM for periodic scans. You may be thinking of the Sentry feature, which isn't required.
ClamXav does include a Sentry feature that provides user defined on-access scanning if this is required. This feature does chronically use system resources if enabled.
 

thatoneguy82

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Jul 23, 2008
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I wouldn't use ClamXav either, unless you want to see all your RAM get used up before your eyes.
I'm inclined to agree with you. I just installed it and looking at the activity monitor it uses a lot more memory than Sophos. It's using about ~100MB whereas Sophos is using ~9MB. I'm not even sure if there is some sort of automatic background scanner.
 

GGJstudios

macrumors Westmere
May 16, 2008
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I'm inclined to agree with you. I just installed it and looking at the activity monitor it uses a lot more memory than Sophos. It's using about ~100MB whereas Sophos is using ~9MB. I'm not even sure if there is some sort of automatic background scanner.
Turn off the Sentry feature.
 

thatoneguy82

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Jul 23, 2008
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Here is the Activity Monitor. It just seems excessive. "SophosUIServer" is of course Sophos and there are 2 for ClamXav, "ClamXav" and "clamscan" that's almost 200MB in memory.

 

GGJstudios

macrumors Westmere
May 16, 2008
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Here is the Activity Monitor. It just seems excessive. "SophosUIServer" is of course Sophos and there are 2 for ClamXav, "ClamXav" and "clamscan" that's almost 200MB in memory.

Image
To get a complete picture, launch Activity Monitor and change "My Processes" at the top to "All Processes", then click on the CPU column heading once or twice, so the arrow points downward (highest values on top). Then see what apps are using system resources.

Second, 200MB is trivial compared to the virtual memory available.

Third, when comparing any apps, look not just at memory usage, but CPU usage, as well.

Finally, the recommendation against Sophos is not about RAM or CPU usage or performance issues at all, but about the added vulnerability of running such an app with elevated privileges, as explained in the links I posted in post #6. There is no need to run any antivirus app all the time (or at all). ClamXav does a good job as a tool to periodically scan for malware, but it's not necessary to have it or any other AV app running all the time.
 

thatoneguy82

macrumors 68000
Jul 23, 2008
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To get a complete picture, launch Activity Monitor and change "My Processes" at the top to "All Processes", then click on the CPU column heading once or twice, so the arrow points downward (highest values on top). Then see what apps are using system resources.

Second, 200MB is trivial compared to the virtual memory available.

Third, when comparing any apps, look not just at memory usage, but CPU usage, as well.

Finally, the recommendation against Sophos is not about RAM or CPU usage or performance issues at all, but about the added vulnerability of running such an app with elevated privileges, as explained in the links I posted in post #6. There is no need to run any antivirus app all the time (or at all). ClamXav does a good job as a tool to periodically scan for malware, but it's not necessary to have it or any other AV app running all the time.
Here you go. I did as you instructed.



It seems to be a lot worse in this view.
 

old-wiz

macrumors G3
Mar 26, 2008
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West Suburban Boston Ma
I get those spam e-mails regularly and the spam filter catches them Sometimes it's UPS, sometimes USPS, sometimes FedEx..none of whom have my e-mail address.

Another spam or scam was supposedly from State of New York about a speeding ticket...I haven't driven in NY in....more than 10 years, and they certainly don't have my e-mail address.

I never open them.
 

GGJstudios

macrumors Westmere
May 16, 2008
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Here you go. I did as you instructed.

It seems to be a lot worse in this view.
It looks like it's performing the initial scan of your system, which makes sense since you just installed it. Naturally, that would take far more resources than monitoring or scanning after the initial scan is complete.