RE: Finding root-kits on Windows

From: Amarante, Rodrigo P. (RPAmaranteat_private)
Date: Wed May 07 2003 - 07:33:35 PDT

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    Ansering your questions:
    
    1st Question - 
    The best resource for "known" rootkits (yes, Greg's is not the only one)
    is Greg's Website and BBS www.rootkit.com
    In his FTP server (you must register with th BBS in order to have
    access) you can find his NTRootkit, along with HE4Hook, NuLl, Hacker
    Defense and some "test" projects (basic) that the users of the
    BBS/Newsgroup are submitting...(For some reason Hacker Defense is
    missing files in www.rootkit.com, but you can get it from the coders
    themselves at www.rootkit.host.sk)
    
    Note...this is old times BBS stuff, so download speed is just not there.
    Be prepared to start a 1.5MB download and
    wait a while for it to finish
    
    2nd Question
    From the ones I've played with (NTRootKit, Hacker Defense) What I said
    is true: a remote network connection won't be filtered by the rootkit
    driver.
    
    
    
    
    
     
    
    
    -----Original Message-----
    From: Harlan Carvey [mailto:keydet89at_private] 
    Sent: Wednesday, May 07, 2003 9:04 AM
    To: forensicsat_private
    
    Please bear with me, as I'd like to address the three posts I see in
    this thread all in one email...
    
    First from the OP (shrink-wrap):
    
    > but on the compromised machine it is impossible* to view these files 
    > or the directory.
    
    Can you elaborate on what you mean by this?  I know it may sound like a
    question w/ an obvious answer, but too many times I've run across folks
    who've examined Windows boxen and made statements like this without any
    sort of background info.  What did you try?  What worked/didn't work?
    
    > After reading more and more on windows rootkits- one of the common 
    > ways to use them is to pick a common string to hide and in my case all
    
    > the files and the directory have the string "drop" as part of their 
    > name.  As a test I created a directory in the root
    of
    > the drive named "dropper" and it also "disappeared".
    
    I am familiar with the technique to which you're referring...this was
    popularized by Greg Hoglund's rootkit techniques.  However, until your
    post, Greg's proof-of-concept NTRootKit was the only one publicly
    available (to the best of my knowledge).  You use plurals throughout
    your post...can you elaborate a little bit on other Windows rootkits you
    found?
    
    > how can I find this root-kit that is hooked into my
    kernel?
    
    From your reading, you should be looking for a device
    driver file.  If a listing from the running machine
    doesn't show any unusual or suspicious drivers, I'd
    suggest that you examine the image file for files
    named "drop*.sys" within the system32 directory.
    
    Would it be possible to get a zipped archive of all of
    the files you listed in your post, as well as any
    other files associated with this, w/ the directory
    structure maintained?  I'd greatly appreciate it.
    
    Further, if the system is still up and running, could
    you document the following and include the output in a
    zipped archive?
    
    1.  output of netstat -an
    2.  output of fport
    3.  results of a comprehensive port scan of the system
    4.  output of pslist.exe, handle.exe, and listdlls.exe
    (all from SysInternals)
    
    Also, I'd be interested in examining a text dump of
    the Registry from the image file.
    
    > BTW, it hasn't matched up with a well-known root-kit
    > yet (like slanret) 
    
    You're right.  Symantec defines slanret as a Trojan,
    though...and that bit of malware was detectable via a
    particular Registry key.
    
    > *=except 'cd'ing, via command prompt only, into the 
    > suspect (drop) directory and 'dir' listing all files
    
    > *without* the "drop" name--possibly an error with
    the
    > root-kit?
    
    Maybe in its architecture.  Remember, you said
    yourself that your reading regarding rootkits
    mentioned the use of a particular string to "hide" the
    files.   Therefore, it would seem obvious that if the
    file did NOT start w/ the target string ("drop", in
    this case) then the files would be viewable.
    
    ----------------------------------------------------
    For Rodrigo:
    
    You said:
    "...most Windows rootkits hide themselves by hooking
    into to System APIs and "filtering" based on a
    keyword..."
    
    Again, like S-W, you use the plural.  Are you familiar
    w/ more than just Greg Hoglund's NTRootkit and
    slanret, that use this technique?  If so, could you
    provide links or more detailed information?
    
    > Another thing worth mentioning is that since it's
    the
    > local kernel that is "patched", a remote connection 
    > (like mapping a network drive to the volume in the 
    > compromised machine) should be clear of any 
    > filtering...
    
    This is interesting.  Have you tested this?  If so,
    can you document your testing procedure and results? 
    I'm very interested, as I'm currently writing a book
    on Windows data forensics.
    
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