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Re: Thanks for arch advice - see my photos here

 
 
Nehmo Sergheyev
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      07-30-2003
Nehmo Sergheyev
> > An attachment ending with "JPG" is just a pic.


Michael Shields
> An attachment or link with a name ending in "jpg" may actually have a
> content-type of anything. It might not be a JPEG picture at all; it
> is possible for it to be an HTML page, an executable, or anything.


Nehmo
I would think the newsreader somehow has to know what to do with a file
once it gets it. I assume it looks at the extension and then opens it or
sends it to another program. Certain extensions and security settings
may cause a warning to pop up.

I would also thing if Outlook Express saw the .jpg extension on a link,
it would get Internet Explorer to render it into a pic.

I don't know how a .jpg can execute. I crossposted this in the hope of
getting an answer.
[The thread started in news:alt.building.construction.]

Is it always safe to click on a .jpg?







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* Nehmo Sergheyev *
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http://home.kc.rr.com/missouri/Susan_Talks.htm






 
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Nehmo Sergheyev
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      07-31-2003
Nehmo
> > I would think the newsreader somehow has to know what to do with a

file
> > once it gets it. I assume it looks at the extension and then opens

it or
> > sends it to another program.


Michael Shields
> Not so. The web server sends a "content-type" along with each file it
> serves. Usually it sends "image/jpeg" along with a file that ends in
> ".jpg", but it could be configured to send anything.


Nehmo
Well, Okay. where would this "content-type" thing be?

Nehmo
> > Is it always safe to click on a .jpg?


Michael
> No. If you don't trust your browser or mailer or newsreader to keep
> you safe from external content, you should get one that you do trust.


Nehmo
I know from experience that I'm probably not safe. But I still wouldn't
hesitate to click on a jpg.

You're not specific with your recommendations.





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* Nehmo Sergheyev *
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http://home.kc.rr.com/missouri/Susan_Talks.htm



 
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Jim Watt
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      07-31-2003
On Thu, 31 Jul 2003 17:16:14 GMT, "Nehmo Sergheyev"
<(E-Mail Removed)> wrote:

>I know from experience that I'm probably not safe. But I still wouldn't
>hesitate to click on a jpg.


As long as it really is a .jpg

One of the trick of the worms is to sent attachments of the form

nice_photo.jpg.scr

which is in fact executable.
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Jim Watt http://www.gibnet.com
 
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Nehmo Sergheyev
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      07-31-2003
Nehmo
> >I know from experience that I'm probably not safe. But I still

wouldn't
> >hesitate to click on a jpg.


Jim Watt
> As long as it really is a .jpg
> One of the trick of the worms is to sent attachments of the form
> nice_photo.jpg.scr
> which is in fact executable.


Nehmo
Another trick I've seen is put the innocuous jpg letters and then to put
a whole bunch of spaces right before the real file extension, hopefully
tricking the clicker into missing the real extension.
Girlslickinggirls.jpg_____________________________ ______.vbs








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* Nehmo Sergheyev *
*******************
http://home.kc.rr.com/missouri/Susan_Talks.htm





 
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Michael Shields
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      08-01-2003
In article <y9cWa.807$(E-Mail Removed) >,
"Nehmo Sergheyev" <(E-Mail Removed)> wrote:
> Well, Okay. where would this "content-type" thing be?


It's sent by the web server along with the file. In Netscape or
Mozilla, you can right-click and select "View Page Info" to see the
types of the page ("text/html") and its images (for example
"image/gif").

> I know from experience that I'm probably not safe. But I still wouldn't
> hesitate to click on a jpg.


A URL ending in ".jpg" may not actually be a JPEG image. It could
potentially be anything. There is no way to be safe; if your browser
is going to execute active content when it finds it, then eventually
it will, because active content could be at any URL.

> You're not specific with your recommendations.


Instead of avoiding attachments and links, get a browser that won't
ever run executables without your explicit permission. Then you won't
need to worry about what to click on. If your current browser is
insecure, complain.
--
Shields.
 
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