Message-ID: <1418821596.20070222150333@SECURITY.NNOV.RU>
Date: Thu, 22 Feb 2007 15:03:33 +0300
From: 3APA3A <3APA3A@...URITY.NNOV.RU>
To: "Andres Tarasco" <atarasco@...il.com>
Cc: bugtraq@...urityfocus.com, full-disclosure@...ts.grok.org.uk
Subject: Re[2]: [Full-disclosure] Microsoft Windows 2000/XP/2003/Vista ReadDirectoryChangesW informaton leak

Dear Andres Tarasco,

Agree,  but  actually,  I  mean  to  store  sensitive  data in different
location (different network share).

There  will  be  one  more  advisory,  it  will demonstrate symlink-like
attacks  on  Windows.  In the same advisory I plan to discuss problem of
secure data in insecure folder mode deeply.

E.g.  it's  quite impossible for administrator to _create_ secure folder
in  insecure  one  without not-quite-race conditions this folder will be
available  for  different bad things (without deleting network share, of
cause).  Under  POSIX  system  this  problem is solvable with umask, for
Windows it seems it was never discussed.



--Thursday, February 22, 2007, 2:29:49 PM, you wrote to 3APA3A@...urity.nnov.ru:

AT> Hi,

AT> You told that as a  workaround that we should never allow "creation of  more
AT> secure folder in less secure ones."

AT> I agree but, as i see..,  that means that also allowing the "Bypass traverse
AT> checking" policy is also a bad idea.

AT> Anyway, there are several scenarios where we could not protect us against
AT> that threat easily, like for example a shared environment with terminal
AT> server/citrix where all our stored documents can be stolen.
AT> In that case, only a software restriction policy will protect us.

AT> regards,

AT> Andres Tarasco



AT> 2007/2/22, 3APA3A <3APA3A@...urity.nnov.ru>:
>>
>>
>>
>> Title:          Microsoft Windows 2000/XP/2003/Vista ReadDirectoryChangesW
>>                 informaton leak
>> Author:         3APA3A, http://securityvulns.com
>> Affected:       Microsoft Windows 2000,XP,2003,Vista
>> Exploitable:    Yes
>> Type:           Remote  (from  local  network), authentication required
>>                 (NULL session was not tested).
>> Class:          Information leak, insecure design
>> CVE:            CVE-2007-0843
>> Original
>> Advisory:
>> http://securityvulns.com/advisories/readdirectorychanges.asp
>> SecurityVulns
>> news:
>> http://securityvulns.com/news/Microsoft/Windows/ReadDirector.html
>>
>>
>> Intro:
>>
>> It's  very simple yet interesting vulnerability. ReadDirectoryChangesW()
>> API  allows  application  to  monitor  directory  changes  in real time.
>> bWatchSubtree  parameter  of  this  functions  allows to monitor changes
>> within  whole  directory  tree  with  of monitored directory. To monitor
>> changes directory must be open with LIST (READ) access. Function returns
>> the   list   of  modified  files  with  a  type  of  modification.  File
>> modification refers to any modification of file record in directory.
>>
>> Vulnerability:
>>
>> ReadDirectoryChangesW()  doesn't  check  user's  permissions  for child
>> child  objects,  making  it's  possible  to  retrieve  information about
>> objects user has no "LIST" permissions.
>>
>> Impact:
>>
>> Any  unprivileged  user with LIST access to parent directory can monitor
>> any  files  in  child directories regardless of subdirectories and files
>> permissions.  Because  by  default  Windows  updates  access time of any
>> accessed  files on NTFS volumes, it makes it possible for user to gather
>> information  about  NTFS-protected files, their names and time of access
>> to  the  files  (reading,  writing,  creation, deletion, renaming, etc).
>> Filenames  may  contain  sensitive information or leak information about
>> user's behavior (e.g. cookies files).
>>
>> In  addition  to  it's own impact, this vulnerability elevates impact of
>> few  different  vulnerabilities  and  common  practices,  to be reported
>> later.
>>
>> Exploit:
>>
>> http://securityvulns.com/files/spydir.c
>>
>> compiled version of Spydir is available from
>>
>> http://securityvulns.com/soft/
>>
>> Usage example:
>>
>> spydir \\corpsrv\corpdata
>>
>> I  believe  you  find  this  utility  useful regardless of this security
>> issue.  It shows names of accessed/modified files for given directory in
>> real time (it seems there are non-security bugs in ReadDirectoryChangesW
>> implementations,  e.g.  you can not see non-ASCII names and some changes
>> are missing).
>>
>> Workaround:
>>
>> Avoid  creation  of  more secure folder in less secure ones. Avoid using
>> sensitive data in documents naming.
>>
>> Vendor (Microsoft):
>>
>> January, 17 2006          Initial vendor notification
>> January, 18 2006          Vendor reply (assigned)
>> January, 26 2006          2nd vendor notification
>> February, 7 2006          3rd vendor notification
>> February, 9 2006          Vendor accepted vulnerability as "service pack
>>                           class" for Windows XP and Windows 2003.
>> February, 9 2006          Accepted to wait until SP
>> February, 22 2006         Vendor gives SP timelines (late 2006 for W2K3
>>                           SP2 and 2007 for XP SP3)
>> February, 22  2007        Public  release,  because  Windows Vista is
>>                           released with same vulnerability.
>>
>>
>> _______________________________________________
>> Full-Disclosure - We believe in it.
>> Charter: http://lists.grok.org.uk/full-disclosure-charter.html
>> Hosted and sponsored by Secunia - http://secunia.com/
>>





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