Re: file hiding under Linux

From: Daniel Nyström (exceat_private)
Date: Tue Jun 24 2003 - 16:29:04 PDT

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    Hello!
    
    This is not a good way of approaching hiding files in Linux ;P As it can at
    best be considered as "security thru obscurity".. heh.. but not even that. :)
    
    When U have gotten used to using a Linux system u will find that u know
    where all binaries are located and if a whereis doesnt turn something up, u
    just use the full path.
    
    What u just demonstrated cannot be thougt of as hiding files, just annoying users :)
    
    A better way to approach file hiding maybe u should take a look at this:
    
    http://www.phrack.org/show.php?p=59&a=6
    
    or try to write a LKM for that purpose.
    
    Have a nice day ;P
    
    Daniel Nyström
    Independent Security Researcher
    ----------------------------------
    exceat_private
    http://www.telhack.tk
    http://exce.ath.cx
    
    ----- Original Message ----- 
    From: <sam_secat_private>
    To: <vuln-devat_private>
    Sent: Monday, June 23, 2003 10:31 PM
    Subject: file hiding under Linux
    
    
    > Hi,
    > 
    > First off I'd like to apologise for my inaptness but I'm new to hacking,
    > but I'm also, or so I'm told, very creative (switched from a humanities major to CS) and am
    > full of new ideas that I'd like to
    > discuss and get feedback on. Ok so I've been working on filehiding for the
    > linux operating system (www.linux.org) that you can download for free
    > and is very popular. But you probably all know this. I was wondering,
    > would it be possible to abuse the linux enviroment to make legitemit users
    > think a certain file was not present. Like, you can set the enviroment
    > variable $PATH to something like "/tmp". In the bourne again shell version
    > 2.05b one can use "export" to set enviroment variables. There might be
    > other techniques but my Linux course hasn't covered them yet. I'm open for
    > ideas though. This technique only works for executing binaries, listing
    > the directory will still find it.
    > 
    > So for hiding the binaries in /usr/bin an example would be:
    > 
    > $ export PATH="/tmp"
    > $ ls
    > -bash: ls: command not found
    > $ echo "hid all files in /usr/bin"
    > hid all files in /usr/bin
    > $ whereis echo
    > -bash: whereis: command not found
    > $
    > 
    > So basically I'm building on this, I'd love some feedback and maybe how to
    > implement this technique in other scenarios.
    > 
    > With regards,
    > Sam
    > 
    



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