FW: Nimda Worm Mitigation

From: Jason Lewis (jlewisat_private)
Date: Wed Sep 19 2001 - 19:32:54 PDT

  • Next message: David LeBlanc: "RE: Please tell me I'm wrong: microsoft.com infected"

    I thought this was worth sharing.  Thanks Nate.
    
    Jason Lewis
    http://www.packetnexus.com
    It's not secure "Because they told me it was secure".
    The people at the other end of the link know less
    about security than you do. And that's scary.
    
    
    On Tue, 18 Sep 2001, Jason Lewis wrote:
    
    > How about something that tails an apache log file and adds ipchains rules
    to
    > kill infected IP's? Anyone want to write it?
    
    I've added ".exe" next to ".cgi" in my httpd.conf.  Then I created
    "root.exe" and "cmd.exe" symlinks to a suid perl script that adds an
    ipchains deny rule for $ENV{'REMOTE_ADDR'}.
    
    ##########################################################################
    #!/usr/bin/perl -w
    
    my $RemoteIP = $ENV{'REMOTE_ADDR'};
    
    if ($RemoteIP =~ /^([0-9.]+)$/)
    {
    	$RemoteIP = $1;      # untainted
    }
    else
    {
    	die "Bad data in RemoteIP: $RemoteIP";
    }
    
    print <<EOF;
    Content-type: text/html
    
    This site not hacked by chinese.
    
    EOF
    
    $ENV{'PATH'} = '/bin:/usr/bin:/sbin';
    
    my $Command = "/usr/local/sbin/ban $RemoteIP CodeBlue";
    
    my $Result = `$Command`;
    
    
    ##########################################################################
    # this is /usr/local/sbin/ban, something I use for various honeypots
    
    /sbin/ipchains -I input -s $1 -j DENY -l
    echo `date` $1 $2 $3 $4 $5 >>  /usr/local/etc/ipchains.deny
    
    #####
    
    This is what my web site looks like if you access it by the IP address:
    
    $ dir IP
    total 8
    lrwxrwxrwx    1 root     root            8 Sep 18 10:21 MSADC -> honeypot
    lrwxrwxrwx    1 root     root            9 Sep 18 10:31 _mem_bin ->
    honeypot/
    lrwxrwxrwx    1 root     root            8 Sep 18 10:21 c -> honeypot
    lrwxrwxrwx    1 root     root            9 Sep 18 10:30 d -> honeypot/
    lrwxrwxrwx    1 root     root           10 Aug  6 13:46 default.ida ->
    index.html
    drwxr-xr-x    3 root     root         4096 Sep 18 10:40 honeypot
    -rw-r--r--    1 root     root          101 Aug  6 02:25 index.html
    lrwxrwxrwx    1 root     root            9 Sep 18 10:31 msadc -> honeypot/
    lrwxrwxrwx    1 root     root            8 Sep 18 10:21 scripts -> honeypot
    
    $ dir IP/honeypot
    total 8
    -rwsr-sr-x    1 root     root          373 Sep 18 11:35 ban.cgi
    lrwxrwxrwx    1 root     root            7 Sep 18 10:33 home.cgi -> ban.cgi
    lrwxrwxrwx    1 root     root            8 Sep 18 10:22 root.exe -> home.cgi
    drwxr-xr-x    3 root     root         4096 Sep 18 10:36 winnt
    
    Hmmmm, I guess I should make the .ida extension executable and symlink
    default.ida to the ban script.  Anyhow, I usually don't hear from an
    infected box more than once.  Feel free to forward this to the list, but
    if you do, please DO NOT include my email address.  I don't like the way
    the archives make everyone's addresses available to spammers.  Kind of
    ironic behavior for a security organization, really. :-)
    
    Cheers,
    
    Nate Waddoups
    Redmond WA USA
    http://www.natew.com
    
    
    
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