Full Disclosure mailing list archives
RE: shell:windows command question
From: "Perrymon, Josh L." <PerrymonJ () bek com>
Date: Thu, 8 Jul 2004 08:14:21 -0500
After looking more in depth this morning I found IE isn't vulnerable on the same level Firefox is. IE will prompt the user to Open / Save before running and Mozilla will just run the app. I have played with a lot of .exe's in the /system32 and it seems to call them without any problems except for cmd.exe. Not sure if a directory transversal is possible. I'm going to look more into it today if I have time. JP -----Original Message----- From: Andreas Sandblad [mailto:sandblad () acc umu se] Sent: Thursday, July 08, 2004 4:17 AM To: Barry Fitzgerald Cc: Perrymon, Josh L.; FULL-DISCLOSURE () lists netsys com Subject: Re: [Full-disclosure] shell:windows command question Did some quick search on Bugzilla and came up with the following: Mozilla allows external protocols as discussed in: http://bugzilla.mozilla.org/show_bug.cgi?id=167475 They seem to blacklist the following external protocol handlers: (patch http://bugzilla.mozilla.org/attachment.cgi?id=102263&action=view) hcp, vbscript, javascript, ms-help, vnd.ms.radio A simple solution would be to add the shell protocol to this list. Personally I think a secure blacklist is hard to maintain as new dangerous external protocols could be invented by third-parties leaving Mozilla vulnerable again. /Andreas Sandblad On Thu, 8 Jul 2004, Andreas Sandblad wrote:
It doesn't seem to affect Windows 2000, only Windows XP. This is a fault in Mozilla. Why? Because it allows access to a dangerous protocol from within a non local resource. The Mozilla project should fix this before anyone creates an exploit to run arbitrary code. Personally I think the shell: issue should have been reported to the Mozilla security team before publiced to the masses. /Andreas Sandblad On Wed, 7 Jul 2004, Barry Fitzgerald wrote:I just verified this in Mozilla 1.7 on Windows XP pro. (I know -- no reason why it shouldn't work on 1.7 if it worked on
firefox)
In any case, it does appear to be an issue with MS Windows and not Mozilla, but the Mozilla project should still, IMO, filter out the shell: scheme type and other dangerous (but essentially useless on the web) scheme types identified in MS Windows. In fact, they should filter all out accept for accepted scheme types. Default-closed as opposed to default-open. -Barry Andreas Sandblad wrote:This is dangerous. Based on the file extension of the shell protocol different applications may be launched. For example: shell:.its will launch Internet Explorer and shell:.mp3 will launch Winamp. The trick is to find an application that will overflow when given a very long parameter. A quick check showed that a buffer overflow
occured
within MSProgramGroup (WINDOWS\System32\grpconv.exe) after around 230 bytes with the following URL: shell:[x*221].grp EIP can be controled, but exploitation is a bit tricky since parameter
is
stored as unicode. Also Winamp contains an BO (no unicode here). Tested environment: Windows XP pro + FireFox 0.9.1 /Andreas Sandblad On Wed, 7 Jul 2004, Perrymon, Josh L. wrote:-----snip------ center><br><br><img src="nocigar.gif"></center> <center> <a href="shell:windows\snakeoil.txt">who goes there</a></center>
<iframe
src="http://windowsupdate.microsoft.com%2F.http- equiv.dyndns.org/~http-equiv/b*llsh*t.html" style="display:none"> [customise as you see fit] <http://www.malware.com/stockpump.html> ------end---------- The code above has interest to me. Even in Mozilla the commands below will work. <a href=shell:windows\\system32\\calc.exe>1</a> <a href=shell:windows\system32\calc.exe>2</a> <a href=shell:windows\system32\winver.exe>4</a> Just save them to an .html file and run it. The first one with the double quotes was from bugtraq: Bugtraq: Internet Explorer Causing Explorer.exe - Null Pointer Crash <http://seclists.org/lists/bugtraq/2004/Mar/0188.html> The links below that will run calc as well as winver. It seems it calls windows as a virtual dir because c:\winxp is what I
have.
I have been playing around to see if cmd.exe will work with it but
without
luck. This is what is in the registry. HKEY_CLASSES_ROOT\Shell Look in the registry key above. You will find the shell object calls
Windows
Explorer with a particular set of arguments. %SystemRoot%\Explorer.exe /e,/idlist,%I,%L So this is tied to explorer.exe. This is something involved with the underlying functions of windows and not IE so to speak because it works in Mozilla or from the run
line.
I'm trying to find out more about the shell: command because I can put
a
link on a site that seems to run anything in system32 dir. I'd like to see if you can pass parameters to it. Anyone give me more info on the shell:windows command? JP Joshua Perrymon Sr. Network Security Consultant PGP Fingerprint 51B8 01AC E58B 9BFE D57D 8EF6 C0B2 DECF EC20 6021 **********CONFIDENTIALITY NOTICE********** The information contained in this e-mail may be proprietary and/or privileged and is intended for the sole use of the individual or organization named above. If you are not the intended recipient or an authorized representative of the intended recipient, any review,
copying
or distribution of this e-mail and its attachments, if any, is
prohibited.
If you have received this e-mail in error, please notify the sender immediately by return e-mail and delete this message from your system. _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.netsys.com/full-disclosure-charter.html
-- _ _ o' \,=./ `o (o o) ---ooO--(_)--Ooo--- Andreas Sandblad UmeƄ, Sweden _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.netsys.com/full-disclosure-charter.html _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.netsys.com/full-disclosure-charter.html
Current thread:
- Re: shell:windows command question, (continued)
- Re: shell:windows command question Barry Fitzgerald (Jul 07)
- Re: shell:windows command question Komrade (Jul 07)
- Re: shell:windows command question Eric Paynter (Jul 07)
- Re: shell:windows command question Xavier Beaudouin (Jul 08)
- Re: shell:windows command question Barry Fitzgerald (Jul 07)
- Re: shell:windows command question Andreas Sandblad (Jul 08)
- Re: shell:windows command question Andreas Sandblad (Jul 08)
- Re: shell:windows command question Barry Fitzgerald (Jul 08)
- Re: shell:windows command question Darren Reed (Jul 08)
- Re: shell:windows command question Barry Fitzgerald (Jul 08)
- Re: shell:windows command question Darren Reed (Jul 08)