Chargen Probe Utility - Metasploit

This page contains detailed information about how to use the auxiliary/scanner/chargen/chargen_probe metasploit module. For list of all metasploit modules, visit the Metasploit Module Library.

Module Overview

Name: Chargen Probe Utility
Module: auxiliary/scanner/chargen/chargen_probe
Source code: modules/auxiliary/scanner/chargen/chargen_probe.rb
Disclosure date: 1996-02-08
Last modification time: 2019-03-05 03:38:51 +0000
Supported architecture(s): -
Supported platform(s): -
Target service / protocol: -
Target network port(s): 19
List of CVEs: CVE-1999-0103

Chargen is a debugging and measurement tool and a character generator service. A character generator service simply sends data without regard to the input. Chargen is susceptible to spoofing the source of transmissions as well as use in a reflection attack vector. The misuse of the testing features of the Chargen service may allow attackers to craft malicious network payloads and reflect them by spoofing the transmission source to effectively direct it to a target. This can result in traffic loops and service degradation with large amounts of network traffic.

Module Ranking and Traits

Module Ranking:

• normal: The exploit is otherwise reliable, but depends on a specific version and can't (or doesn't) reliably autodetect. More information about ranking can be found here.

Basic Usage

This module is a scanner module, and is capable of testing against multiple hosts.

msf > use auxiliary/scanner/chargen/chargen_probe
msf auxiliary(chargen_probe) > show options
    ... show and set options ...
msf auxiliary(chargen_probe) > set RHOSTS ip-range
msf auxiliary(chargen_probe) > exploit

Other examples of setting the RHOSTS option:

Example 1:

msf auxiliary(chargen_probe) > set RHOSTS 192.168.1.3-192.168.1.200 

Example 2:

msf auxiliary(chargen_probe) > set RHOSTS 192.168.1.1/24

Example 3:

msf auxiliary(chargen_probe) > set RHOSTS file:/tmp/ip_list.txt

Required Options

• RHOSTS: The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'

Knowledge Base

    msf > use auxiliary/scanner/chargen/chargen_probe
    msf auxiliary(chargen_probe) > set rhosts 127.0.0.1
    rhosts => 127.0.0.1
    msf auxiliary(chargen_probe) > set verbose true
    verbose => true
    msf auxiliary(chargen_probe) > run

    [*] 127.0.0.1:19 - Response: !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefgh
    "#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghi
    #$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghij
    $%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijk
    %&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijkl
    &'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklm
    '()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmn
    ()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmno
    )*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnop
    *+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopq
    +,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqr
    ,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrs
    -./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrst
    ./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghi

    [+] 127.0.0.1:19 answers with 1022 bytes (headers + UDP payload)
    [*] Scanned 1 of 1 hosts (100% complete)
    [*] Auxiliary module execution completed

Go back to menu.

Msfconsole Usage

Here is how the scanner/chargen/chargen_probe auxiliary module looks in the msfconsole:

msf6 > use auxiliary/scanner/chargen/chargen_probe

msf6 auxiliary(scanner/chargen/chargen_probe) > show info

       Name: Chargen Probe Utility
     Module: auxiliary/scanner/chargen/chargen_probe
    License: Metasploit Framework License (BSD)
       Rank: Normal
  Disclosed: 1996-02-08

Provided by:
  Matteo Cantoni <[email protected]>

Check supported:
  No

Basic options:
  Name       Current Setting  Required  Description
  ----       ---------------  --------  -----------
  BATCHSIZE  256              yes       The number of hosts to probe in each set
  FILTER                      no        The filter string for capturing traffic
  INTERFACE                   no        The name of the interface
  PCAPFILE                    no        The name of the PCAP capture file to process
  RHOSTS                      yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
  RPORT      19               yes       The target port (UDP)
  SNAPLEN    65535            yes       The number of bytes to capture
  THREADS    10               yes       The number of concurrent threads
  TIMEOUT    500              yes       The number of seconds to wait for new data

Description:
  Chargen is a debugging and measurement tool and a character 
  generator service. A character generator service simply sends data 
  without regard to the input. Chargen is susceptible to spoofing the 
  source of transmissions as well as use in a reflection attack 
  vector. The misuse of the testing features of the Chargen service 
  may allow attackers to craft malicious network payloads and reflect 
  them by spoofing the transmission source to effectively direct it to 
  a target. This can result in traffic loops and service degradation 
  with large amounts of network traffic.

References:
  https://nvd.nist.gov/vuln/detail/CVE-1999-0103
  http://tools.ietf.org/html/rfc864

Module Options

This is a complete list of options available in the scanner/chargen/chargen_probe auxiliary module:

msf6 auxiliary(scanner/chargen/chargen_probe) > show options

Module options (auxiliary/scanner/chargen/chargen_probe):

   Name       Current Setting  Required  Description
   ----       ---------------  --------  -----------
   BATCHSIZE  256              yes       The number of hosts to probe in each set
   FILTER                      no        The filter string for capturing traffic
   INTERFACE                   no        The name of the interface
   PCAPFILE                    no        The name of the PCAP capture file to process
   RHOSTS                      yes       The target host(s), range CIDR identifier, or hosts file with syntax 'file:<path>'
   RPORT      19               yes       The target port (UDP)
   SNAPLEN    65535            yes       The number of bytes to capture
   THREADS    10               yes       The number of concurrent threads
   TIMEOUT    500              yes       The number of seconds to wait for new data

Advanced Options

Here is a complete list of advanced options supported by the scanner/chargen/chargen_probe auxiliary module:

msf6 auxiliary(scanner/chargen/chargen_probe) > show advanced

Module advanced options (auxiliary/scanner/chargen/chargen_probe):

   Name                   Current Setting  Required  Description
   ----                   ---------------  --------  -----------
   CHOST                                   no        The local client address
   CPORT                                   no        The local client port
   GATEWAY_PROBE_HOST     8.8.8.8          yes       Send a TTL=1 random UDP datagram to this host to discover the default gateway's MAC
   GATEWAY_PROBE_PORT                      no        The port on GATEWAY_PROBE_HOST to send a random UDP probe to (random if 0 or unset)
   NUM_REQUESTS           1                no        Number of requests to send
   SECRET                 1297303073       yes       A 32-bit cookie for probe requests.
   SRCIP                                   no        Use this source IP
   ScannerMaxResends      10               yes       The maximum times to resend a packet when out of buffers
   ScannerRecvInterval    30               yes       The maximum numbers of sends before entering the processing loop
   ScannerRecvQueueLimit  100              yes       The maximum queue size before breaking out of the processing loop
   ScannerRecvWindow      15               yes       The number of seconds to wait post-scan to catch leftover replies
   ShowProgress           true             yes       Display progress messages during a scan
   ShowProgressPercent    10               yes       The interval in percent that progress should be shown
   VERBOSE                false            no        Enable detailed status messages
   WORKSPACE                               no        Specify the workspace for this module

Auxiliary Actions

This is a list of all auxiliary actions that the scanner/chargen/chargen_probe module can do:

msf6 auxiliary(scanner/chargen/chargen_probe) > show actions

Auxiliary actions:

   Name  Description
   ----  -----------

Evasion Options

Here is the full list of possible evasion options supported by the scanner/chargen/chargen_probe auxiliary module in order to evade defenses (e.g. Antivirus, EDR, Firewall, NIDS etc.):

msf6 auxiliary(scanner/chargen/chargen_probe) > show evasion

Module evasion options:

   Name  Current Setting  Required  Description
   ----  ---------------  --------  -----------

Go back to menu.

Related Pull Requests

• #11523 Merged Pull Request: MSF5: Remove unneeded RHOST deregister in scanners
• #8716 Merged Pull Request: Print_Status -> Print_Good (And OCD bits 'n bobs)
• #8338 Merged Pull Request: Fix msf/core and self.class msftidy warnings
• #6655 Merged Pull Request: use MetasploitModule as a class name
• #6648 Merged Pull Request: Change metasploit class names
• #6139 Merged Pull Request: Remove bad references (dead links)
• #3837 Merged Pull Request: chargen src IP spoofing
• #3044 Merged Pull Request: chargen_probe report service as udp
• #2802 Merged Pull Request: Tidy up for release

References

• CVE-1999-0103
• http://tools.ietf.org/html/rfc864

See Also

Check also the following modules related to this module:

• auxiliary/scanner/discovery/udp_probe
• post/windows/wlan/wlan_probe_request
• exploit/linux/local/systemtap_modprobe_options_priv_esc
• post/hardware/automotive/canprobe

Related Nessus plugins:

• Chargen UDP Service Remote DoS

Authors

Matteo Cantoni <goony[at]nothink.org>

Version

This page has been produced using Metasploit Framework version 6.1.24-dev. For more modules, visit the Metasploit Module Library.

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