Author Topic: non-english (Japanese) email subject causes Virus warning  (Read 5765 times)

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Offline AlexFeren

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non-english (Japanese) email subject causes Virus warning
« on: February 27, 2009, 01:59:40 PM »
Hello,
using Home v4.8.
When wife sends/receives email with non-english (Japanese) subject (email's body's irrelevant, and no attachments) she gets a warning that there's a possibility of virus.
Is this a known fault? (I can't find any mention of this in Knowledge Base.)
Alex

Offline igor

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Re: non-english (Japanese) email subject causes Virus warning
« Reply #1 on: February 27, 2009, 05:08:19 PM »
Any particular subject, or it doesn't matter?
What exactly does the warning say?

Offline AlexFeren

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Re: non-english (Japanese) email subject causes Virus warning
« Reply #2 on: March 01, 2009, 09:18:17 AM »
Igor,
thanks for asking. Attached is the warning (minus identify of Sender). Forgot to mention, we're talking about Outlook 2007 using Hotmail account.
Alex

Offline Iso-G

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Re: non-english (Japanese) email subject causes Virus warning
« Reply #3 on: March 01, 2009, 04:05:04 PM »
There is no problem with Japanese emails, though I have used avast! 4 since 2003.
Quote
Attached is the warning
Dose the subject include sequence whitespaces ?
I hope the explanation of "Heuristic Page" in the avast's help.chm helps you.
Windows XP Home SP3 / avast! 6.0 Free Antivirus (Japanese) / Microsoft Security  Essentials(v2,Japanese) / COMODO Firewall 5.3 (D+(full),English) / Secunia Personal Software Inspector (v2,English) / Opera / Thunderbird 3 / Open Office 3

Offline AlexFeren

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Re: non-english (Japanese) email subject causes Virus warning
« Reply #4 on: March 02, 2009, 11:15:00 AM »
Dose the subject include sequence whitespaces ?
I hope the explanation of "Heuristic Page" in the avast's help.chm helps you.
The title includes all Japanese characters. Obviously it seems Avast can't handle the Japanese character-set and and interprets these characters in Subject as suspicious.
As per original post, the above warning appears on all emails with Subject in Japanese.
« Last Edit: March 02, 2009, 11:17:48 AM by AlexFeren »

Offline RejZoR

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Re: non-english (Japanese) email subject causes Virus warning
« Reply #5 on: March 02, 2009, 12:28:25 PM »
Looks like Internet mail provider isn't UNICODE and treats so many ???? as possibly malicious mail. Could be something else though...
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Offline Lisandro

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Re: non-english (Japanese) email subject causes Virus warning
« Reply #6 on: March 02, 2009, 01:39:42 PM »
Obviously it seems Avast can't handle the Japanese character-set and and interprets these characters in Subject as suspicious.
I don't think so. If this is the case, we won't have Japanese users, Arabian ones, etc.
The character set is not the problem.
Anyway, you can change heuristic options in the email providers to relax the detection.
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Offline igor

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Re: non-english (Japanese) email subject causes Virus warning
« Reply #7 on: March 03, 2009, 02:23:19 PM »
What have you set in Control Panel / Regional and Language Options / Advanced / Language for non-Unicode programs?
If there isn't Japanese there, does it help if you set so?

Offline AlexFeren

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Re: non-english (Japanese) email subject causes Virus warning
« Reply #8 on: March 04, 2009, 02:37:29 PM »
Email provider is Hotmail and it certainly does handle Japanese (both Subject and content). Email client is Outlook 2007 and it definately does handle Japanese (both Subject and content).
Wife's account is set (Region) for both English and Japanese via Vista's IME (ie. language toolbar).
There shouldn't be a need for me to relax any kind of security feature, quite the opposite, I want all the protection Avast can provide.
Obviously Avast's Outlook plugin has a problem with Japanese character set, non-English HTTP email (as provided by Hotmail), or both.
« Last Edit: March 04, 2009, 02:45:01 PM by AlexFeren »

Offline igor

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Re: non-english (Japanese) email subject causes Virus warning
« Reply #9 on: March 04, 2009, 02:51:38 PM »
What have you set in Control Panel / Regional and Language Options / Advanced / Language for non-Unicode programs?
If there isn't Japanese there, does it help if you set so?

Offline AlexFeren

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Re: non-english (Japanese) email subject causes Virus warning
« Reply #10 on: March 04, 2009, 03:04:14 PM »
What have you set in Control Panel / Regional and Language Options / Advanced / Language for non-Unicode programs?
If there isn't Japanese there, does it help if you set so?
Control Panel / Regional and Language Options / Administrative / Language for non-Unicode programs is set to English which is what most of us would set it to for programs that don't support Unicode.

Did additional testing. If there's at least one English character (I tested at beginning and then at end) in the Subject, the Avast's Outlook plugin doesn't produce the warning. Further evidence that Avast doesn't understand Japanese Subjects.

Offline igor

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Re: non-english (Japanese) email subject causes Virus warning
« Reply #11 on: March 04, 2009, 03:06:57 PM »
If the language for non-Unicode programs is set to English, then of course it doesn't understand the characters (being an Ansi program at the moment) - all characters get converted to question marks by the system.

Which, however, doesn't explain why it should consider the subject suspicious...

Offline AlexFeren

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Re: non-english (Japanese) email subject causes Virus warning
« Reply #12 on: March 04, 2009, 03:11:05 PM »
If the language for non-Unicode programs is set to English, then of course it doesn't understand the characters (being an Ansi program at the moment) - all characters get converted to question marks by the system.
That Windows' setting is specifically for non-Unicode programs. I have looked at Avast's manual and it doesn't mention Unicode. However, given that Avast is distributed for customers around the world and given that it's a modern program, I assumed it was. So, it's not? Rather disappointing.
« Last Edit: March 04, 2009, 03:21:17 PM by AlexFeren »

Offline igor

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Re: non-english (Japanese) email subject causes Virus warning
« Reply #13 on: March 04, 2009, 03:20:45 PM »
Some of its parts (drivers and the surrounding areas) are, some parts (most of the GUI) are not. So, it basically requires having the "correct" language (for non-Unicode programs) set, if everything should work 100%.
Of course, that's a problem if you work with multiple languages (with different encodings), or if there are multiple users on the computer, each using a different language.

Seing the code for the subject check, I can understand the problem... however, it's not clear what to do about it. The subject check may have some sense a couple of years ago, but it's mostly useless today - so the best thing to do is to remove this check/option alltogether, which will most likely happen in avast! 5.0 (even though it will be fully Unicode).
You can safely disable the "Subject structure check" on the customization page of e-mail heuristics, you really won't miss anything.

Offline AlexFeren

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Re: non-english (Japanese) email subject causes Virus warning
« Reply #14 on: March 04, 2009, 03:22:47 PM »
Igor. Thanks. /Alex