Security Basics mailing list archives

RE: READ RECIEPTS automatically generated


From: jlewis1957 () netscape net (Jeff Lewis)
Date: Wed, 28 Jan 2004 11:41:29 -0500

"Muhammad Naseer" <naseer () digitallinx com> wrote:

Don't read HTML mails. Turn off reading HTML mails from your outlook
settings. Always read mails in PLAIN TEXT. Don't send READ RECIEPTS 
back to any user. I guess you will understand the rest here.

I'll be reading all THOSE emails with Thunderbird and have them transferred to a different account rather than my 
normal business account. That doesn't help my users though who use Outlook everyday, and THINK that they are doing the 
right thing.

If they are set up exactly like I am, those read receipts will get through. 

All my emails were read as if they were in the restricted security zone and all settings in that zone are at disable 
with a few at prompt me. After review, the only change I've made is that Outlook XP was set to "Send immediately when 
connected" and I've turned that off.

Found out how to change everything to plain text at http://support.microsoft.com/?kbid=307594 and also some good 
information at http://www.slipstick.com/dev/code/zaphtml.htm

Of course, NEVER actually READING the message helps. To that end, Russ Cooper has a good Outlook security review 
document entitled "How Active is Active Content in Email?" at http://www.ntbugtraq.com/default.asp?sid=1&pid=47&aid=56

Although I took Russ's advice, I doubt that I will be able to convince many of my users to turn off the damned Preview 
Pane much less eliminating RTF or HTML, but I will start to work on them. I never realized how powerful the AutoPreview 
function can be when just trying to weed out spam. I had long ago dismissed this as adding to much "noise" to the view. 
Now I love it.

I learned that spammers can log keywords on their website from an html-based email message that was sent to you when 
you view that email. They can then compare their webserver logs to email addresses to validate the address. They 
certainly can't read an NDR now can they? This is certainly an effective stealth read receipt. I also read up on MSGTAG.

Alas, I STILL DO NOT UNDERSTAND why my client (Outlook XP) generated the receipt.

I have to go through these stored SPAMS (stored for a future bayesian filter install) and find the ones that sent it to 
discover the technique. Sorry for not having done this for you all already.

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