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As you know Gmail scans attachment for viruses (when using native web interface). I was wondering if Gmail is doing the same thing when used by email client such as Thunderbird ?

If not is there possibility to turn it on? or I need to enforce local antivirus protection such as Avast ?

I was googling this stuff nearly hour, but couldn't find any answer so thought someone here could help me. I'm a full time Linux/Mac user and I dealing with a Windows machine here, it's just been a long time since and I'm bit out of date :)

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migrated from Mar 29 '12 at 22:04

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up vote 1 down vote accepted

Well, the official documentation states that:

"Gmail automatically scans every attachment when it's delivered to you, and again each time you open a message. Attachments you send are also scanned."

So, it should be scanned, but I decided to check anyway, using IMAP and a PDF Exploit test file (
Outgoing: SMTP session is rejected as soon as gmail sees the attachment.
Incoming: The SMTP session was also rejected.
Server reply:

Our system detected an illegal attachment on your message. Please
   552-5.7.0 visit to
   552 5.7.0 review our attachment guidelines. 

So, in conclusion - it works! But, I really don't think that their scanner is smart enough to find more elaborate malware, so this is not a substitute for endpoint protection, such as Kaspersky, ESET, McAffee or Symantec.

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thank you for this – equivalent8 Apr 20 '12 at 16:42
You're welcome! – Temikus Apr 21 '12 at 17:54

Hmmmm. I'm going to send myself a file where VirusTotal comes up with a lot of hits. That should test it. All you have to do is rename the .exe to .fake, and gmail let's it by. Never tried an iffy PUP file though. We'll see.

My real concern is that .jpg's and scripts can contain viruses. The very security gmail provides with 128bit encryption prevents my antivirus from scanning the message for hidden suspicious code. I have always been virus free because I refuse to store email on my computer.

But now I need something to use 24-hours. I don't like being logged into Google with a browser because I hate being tracked, so the browser notification addons won't cut it.

Setting IMAP protocol not to store mail on my drive works quite nicely. But Avast gripes that it can't protect me. Makes me really nervous. Had a virus scare today and I immediately suspected Thunderbird.

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If it's a .fake file, then there's no risk of it being executed by the user on accident. There's also no way to embed a working virus into a JPEG file or other image types. There was a remote code execution exploit in the way Windows handled WMF images, but this has been patched long ago. The only people who really need to worry about malicious image files today are webmasters, since web servers can be tricked into executing code inside of a JPEG or other traditionally nonexecutable formats. – Lèse majesté Apr 8 '12 at 22:09
Also, whether or not you store emails locally is irrelevant in regards to preventing virus infection. Even if you use IMAP, you're just as vulnerable to all email infection methods. And it's perfectly safe to use Thunderbird even without an AV installed as long as you don't download and execute random files. Similarly, you can use webmail without being "tracked" locally by simply using a browser like Chrome or Firefox that has an incognito/private browsing mode. – Lèse majesté Apr 8 '12 at 22:13
– Lèse majesté thank you for your comments – equivalent8 Apr 20 '12 at 16:43
Mel, did you try it ? :) – equivalent8 Apr 20 '12 at 16:43

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