[Esa-l]feeble.hey!dora.exploit part.II (fwd)

John D. Hardin jhardin at impsec.org
Thu May 31 07:04:51 PDT 2001

Here is yet more justification for defanging images in HTML mail if
you are supporting Eudora users...

 John Hardin KA7OHZ   ICQ#15735746   http://www.wolfenet.com/~jhardin/
 jhardin at wolfenet.com      pgpk -a finger://gonzo.wolfenet.com/jhardin
  768: 0x41EA94F5 - A3 0C 5B C2 EF 0D 2C E5  E9 BF C8 33 A7 A9 CE 76 
 1024: 0xB8732E79 - 2D8C 34F4 6411 F507 136C  AF76 D822 E6E6 B873 2E79
  An entitlement beneficiary is a person or special interest group
  who didn't earn your money, but demands the right to take your
  money because they *want* it.
                                  -- John McKay, _The Welfare State:
                                     No Mercy for the Middle Class_
   1251 days until the Presidential Election

---------- Forwarded message ----------
Date: Mon, 28 May 2001 19:48:42 -0700 (PDT)
From: "http-equiv at excite.com" <http-equiv at excite.com>
To: bugtraq at securityfocus.com
Subject: feeble.hey!dora.exploit part.II

Monday, May 28, 2001 

Silent delivery and installation of an executable on a target computer. This
can be accomplished with the default installation of the mail client Eudora

'allow executables in HTML content' DISABLED
'use Microsoft viewer' ENABLED

The manufacturer http://www.eudora.com has done a tremendous job of shutting
down all possibilities of scripting and all other necessaries to achieve the
following result.  See:


However there still remains a number of good possibilities. One of which is
the following that we find to be quite interesting.

1. Using the POWAH! of Internet Explorer, we create yet another HTML mail
message as follows: 

<FORM action="cid:master.malware.com" method=post target=new><button 
 color=#0000ff><u>http://www.malware.com</u></font></button> </FORM>
<DEFANGED_IMG SRC="cid:master.malware.com" height=1 width=1><DEFANGED_IMG
SRC="cid:http://www.malware.com" height=1 width=1>

Where our first image is our executable. Our second image comprises a simple
JavaScripting and ActiveX control. 

What happens is, once the mail message is opened in Eudora 5.1, the two
'embedded' images are silently and instantly transferred to the 'Embedded'

What we then do is create a simple html form and button. Owing to the POWAH!
of Internet Explorer, we are able to create this button with a transparent
background. In addition, we are able to dispose of the border of this
button, which combined with the transparent background gives us nothing.
That is, we have a fully functional form and button but we are not able to
see it.  We then create a fake link and incorporate that into our invisible
button. We then embed our simple JavaScripting and ActiveX control into our
invisible button and fire it off to our target computer:

before click

(screen shot: http://www.malware.com/heydora.jpg 62KB)

after click:

(screen shot: http://www.malware.com/hey!dora.jpg 62KB)

The recipient is then lulled into clicking on the "link". What that does is
pull our html file comprising our simple JavaScripting and ActiveX control
out of the embedded folder and into a new Internet Explorer Window. 

Because our *.exe and our simple JavaScripting and ActiveX control reside in
the same folder [the so-called "Embedded' folder], and because it is
automatically opened in our new Internet Explorer Window, everything is

No warnings. No nothing.

The *.exe is executed instantly. 

2. Working Example. Harmless *.exe. incorporated. Tested on win98, with
IE5.5 (all of its patches and so-called service packs), default Eudora 5.1
with 'use Microsoft viewer'  ENABLED and 'allow executables in HTML content'

The following is in plaintext. We are unable to figure out how to import a 
single message into Eudora's inbox. Perhaps some bright spark knows.
Otherwise, incorporate the text sample into a telnet session or other and
fire off to your Eudora inbox: 


Notes: disable 'use Microsoft viewer' 


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