Default Honeyd Scripts

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honeypots for windows
Chapter 7 - Honeyd Service Scripts
Honeypots for Windows
by Roger A. Grimes
Apress 2005
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The Windows version of Honeyd (http://www.securityprofiling.com/honeyd/honeyd.shtml) comes with three default scripts located in the \scripts folder. See Table 7-1 for their names and descriptions.

Table 7-1: Default Scripts in the Windows Version of Honeyd

Script Name

Language

Description

Router-telnet.pl

Perl

Mimics a generic telnet logon session to a Cisco router

Test.sh

Shell

Mimics a SSH logon session

Web.sh

Shell

Mimics an IIS 5.0 default home web page with standard directories

The default scripts that arrive with the Windows version of Honeyd have the distinct advantage of not being compressed in a Unix archive file format. Unix-style scripts are usually Gzipped and/or stored as tarballs (covered in Chapter 5), so they must be uncompressed to their plain-text script formats.

Unfortunately, every script, whether included with the Windows version of Honeyd or downloaded from the Honeyd web site, contains scripting commands that must be converted to Windows-style commands to run appropriately. Let’s start with examining the three default scripts that come with the Windows version of Honeyd.

SSH Test Script

The Test.sh service script, shown in Listing 7-1, is appropriately named. It is a short script, barely mimicking a SSH login session. (SSH command shells normally run on TCP port 23.) It prints the following line on connection:

 SSH-1.5-2.40 

Listing 7.1: Source Code of Test.sh

image from book
 DATE=`date`  echo "$DATE: Started From $1 Port $2" >> /tmp/log  echo SSH-1.5-2.40  while read name  do          echo "$name" >> /tmp/log          echo "$name"  done 
image from book

It then records any typed in data, potentially tracking login names and passwords entered by the intruder. The information is saved, along with the date, to a log file. This simple script can be executed as a test script to make sure Honeyd is working correctly or modified with more functionality.

Unfortunately, even this simple service script needs modification in order to work properly on a Windows system. The log file path and name need to be converted to Windows syntax. Listing 7-2 shows the change, using ssh.log as the file name.

Listing 7.2: Modified Test.sh

image from book
 DATE=`date`  echo "$DATE: Started From $1 Port $2" >> ssh.log  echo SSH-1.5-2.40  while read name  do          echo "$name" >> ssh.log          echo "$name"  done 
image from book

This script is very rudimentary.

Cisco Telnet Session Script

Listing 7-3 shows the Perl source code of Router-telnet.pl. This script was created by Dr. Provos and mimics a generic telnet session to a Cisco router. It first displays a generic privacy disclaimer warning users that all activity may be monitored. This is an important warning that should be included in all honeypot service scripts. As explained in Chapter 1, the use of a honeypot may result in additional legal responsibilities and liabilities. Without appropriate disclosure, hackers might be able to claim that their expectation of privacy was violated or that their communications were monitored without their consent. A disclosure, like the one presented in Router-telnet.pl, may satisfy the legal requirement of both claims.

Listing 7.3: Source Code of Router-telnet.pl

image from book
 # Copyright 2002 Niels Provos <provos@citi.umich.edu>  # All rights reserved.  # For the license refer to the main source code of Honeyd.  # Don't echo Will Echo Will Surpress Go Ahead  $return = pack('ccccccccc', 255, 254, 1, 255, 251, 1, 255, 251, 3);  syswrite STDOUT, $return, 9;  $string =  "Users (authorized or unauthorized) have no explicit or\r  implicit expectation of privacy. Any or all uses of this\r  system may be intercepted, monitored, recorded, copied,\r  audited, inspected, and disclosed to authorized site,\r  and law enforcement personnel, as well as to authorized\r  officials of other agencies, both domestic and foreign.\r  By using this system, the user consents to such\r  interception, monitoring, recording, copying, auditing,\r  inspection, and disclosure at the discretion of authorized\r  site.\r  \r  Unauthorized or improper use of this system may result in\r  administrative disciplinary action and civil and criminal\r  penalties. By continuing to use this system you indicate\r  your awareness of and consent to these terms and conditions\r   of use. LOG OFF IMMEDIATELY if you do not agree to the\r  conditions stated in this warning.\r  \r  \r  \r  User Access Verification\r  ";  syswrite STDOUT, $string;  open(O, ">C:\\fff");  $count = 0;  while ($count < 3) {    do {      $count++;      syswrite STDOUT, "\r\n";      $word = read_word("Username: ", 1);    } while (!$word && $count < 3);    if ($count >= 3 && !$word) {      exit;    }    $password = read_word("Password: ", 0);    if (!$password) {      syswrite STDOUT, "% Login invalid\r\n";    } else {      syswrite STDERR, "Attempted login: $word/$password";      syswrite STDOUT, "% Access denied\r\n";    }  }  exit;  sub read_word {    local $prompt = shift;    local $echo = shift;    local $word;    syswrite STDOUT, "$prompt";    $word = "";    $alarmed = 0;    eval {      local $SIG{ALRM} = sub { $alarmed = 1; die; };      alarm 30;      $finished = 0;      do {        $nread = sysread STDIN, $buffer, 1;        print O "RET: " . $nread . " BUF: " . $buffer . "\n";        die unless $nread;        if (ord($buffer) == 0) {      ;#ignore        } elsif (ord($buffer) == 255) {       sysread STDIN, $buffer, 2;        } elsif (ord($buffer) == 13 || ord($buffer) == 10) {       syswrite STDOUT, "\r\n" if $echo;       $finished = 1;        } else {       syswrite STDOUT, $buffer, 1 if $echo;       $word = $word.$buffer;        }      } while (!$finished);      alarm 0;    };    syswrite STDOUT, "\r\n" if $alarmed || ! $echo;    if ($alarmed) {      syswrite STDOUT, "% $prompt timeout expired!\r\n";      return (0);    }    return ($word);  } 
image from book

The script then prompts the connecting user to log in with the text prompt:

 User Access Verification  Username: 

This is the standard text presented when telnetting to a Cisco router, although sometimes the exact text is not presented until after the first failed login. The typed-in login name is echoed back to the user, and when an Enter keypress is detected (indicating the end of the user name), the user is prompted for her password. No matter what login name and password are entered, the result is an error message indicating an invalid login. The invalid login messages are as follows:

 %Login invalid  %Access denied 

The script even contains a realistic timeout provision. If the connected user has not successfully typed in both a login name and password in 30 seconds, the user will be given the following message:

 timeout expired! 

This is also an accurate behavior of most Cisco routers. Figure 7-1 shows the screen honeypot intruders would see.

image from book
Figure 7-1: Example of the Router-telnet Perl script in action

IIS Web Emulation

The Web.sh script, shown in Listing 7-4, contains a simple emulated IIS 5.0 web page. The script looks for the following HTTP request:

 GET .scripts. *cmd.exe. *dir.* HTTP/1.0 

Listing 7.4: Source Code of Web.sh

image from book
 #!/bin/sh  REQUEST=""  while read name  do       LINE=`echo "$name" | egrep -i "[a-z:]"`       if [ -z "$LINE" ]       then  break       fi       echo "$name" >> /tmp/log  NEWREQUEST=`echo "$name" | grep "GET .scripts.*cmd.exe.*dir.* HTTP/1.0"`       if [ ! -z "$NEWREQUEST" ] ; then            REQUEST=$NEWREQUEST       fi  done  if [ -z "$REQUEST" ] ; then       cat << _eof_  HTTP/1.1 404 NOT FOUND  Server: Microsoft-IIS/5.0  P3P: CP='ALL IND DSP COR ADM CONo CUR CUSo IVAo IVDo PSA  Content-Location: http://cpmsftwbw27/default.htm  Date: Thu, 04 Apr 2002 06:42:18 GMT  Content-Type: text/html  Accept-Ranges: bytes  <html><title>You are in Error</title>  <body>  <h1>You are in Error</h1>  O strange and inconceivable thing! We did not really die, we were not really buried,  we were not really crucified and raised again, but our imitation was but a figure,  while our salvation is in reality. Christ was actually crucified, and actually  buried,  and truly rose again; and all these things have been vouchsafed to us, that we, by  imitation communicating in His sufferings, might gain salvation in reality. O  surpassing loving-kindness! Christ received the nails in His undefiled hands and  feet, and endured anguish; while to me without suffering or toil, by the fellowship  of His pain He vouchsafed salvation.  <p>  St. Cyril of Jerusalem, On the Christian Sacraments.  </body>  </html>  _eof_       exit 0  fi  DATE=`date`  cat << _eof_  HTTP/1.0 200 OK  Date: $DATE  Server: Microsoft-IIS/5.0  Connection: close  Content-Type: text/plain   Volume in drive C is Webserver   Volume Serial Number is 3421-07F5   Directory of C:\inetpub  01-20-02   3:58a      <DIR>          .  08-21-01   9:12a      <DIR>          ..  08-21-01  11:28a      <DIR>          AdminScripts  08-21-01   6:43p      <DIR>          ftproot  07-09-00  12:04a      <DIR>          iissamples  07-03-00   2:09a      <DIR>          mailroot  07-16-00   3:49p      <DIR>          Scripts  07-09-00   3:10p      <DIR>          webpub  07-16-00   4:43p      <DIR>          wwwroot               0 file(s)              0 bytes              20 dir(s)     290,897,920 bytes free  _eof_ 
image from book

This connection request is often associated with attackers and scanning malware looking for insecure IIS servers. If detected, the script will respond with what looks like a directory listing of a default IIS 5.0 server installation:

 Directory of C:\inetpub  01-20-02   3:58a      <DIR>          .  08-21-01   9:12a      <DIR>          ..  08-21-01  11:28a      <DIR>          AdminScripts  08-21-01   6:43p      <DIR>          ftproot  07-09-00  12:04a      <DIR>          iissamples  07-03-00   2:09a      <DIR>          mailroot  07-16-00   3:49p      <DIR>          Scripts  07-09-00   3:10p      <DIR>          webpub  07-16-00   4:43p      <DIR>          wwwroot               0 file(s)              0 bytes              20 dir(s)     290,897,920 bytes free 

If the request is anything else, an emulated 404 (file not found) error message is sent, along with some religious bible quotations. All HTTP requests are logged to a file. If this limited script is used, the following changes should be made:

  • Convert the log file location and name to Windows style.

  • Change the Content-Location: field to reflect the correct web address.

  • Change the drive volume label to something other than Webserver.

  • Change the 404 error text to something other than the default Christian quote.

  • Change the number of bytes free and folder times and dates.

These changes should be made so that inquiring hackers don’t see the default text associated with Honeyd’s IIS Web.sh script.

None of the default scripts are overly interesting or complicated, but they are great for using as a base when creating your own service scripts.

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Honeypots for Windows
Honeypots for Windows (Books for Professionals by Professionals)
ISBN: 1590593359
EAN: 2147483647
Year: 2006
Pages: 119

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