Rapid7 Vulnerability & Exploit Database

DHCP Client Bash Environment Variable Code Injection (Shellshock)

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DHCP Client Bash Environment Variable Code Injection (Shellshock)



This module exploits the Shellshock vulnerability, a flaw in how the Bash shell handles external environment variables. This module targets dhclient by responding to DHCP requests with a malicious hostname, domainname, and URL which are then passed to the configuration scripts as environment variables, resulting in code execution.


  • scriptjunkie
  • apconole <apconole@yahoo.com>
  • Stephane Chazelas
  • Ramon de C Valle <rcvalle@metasploit.com>


Module Options

To display the available options, load the module within the Metasploit console and run the commands 'show options' or 'show advanced':

msf > use auxiliary/server/dhclient_bash_env
msf auxiliary(dhclient_bash_env) > show actions
msf auxiliary(dhclient_bash_env) > set ACTION < action-name >
msf auxiliary(dhclient_bash_env) > show options
    ...show and set options...
msf auxiliary(dhclient_bash_env) > run 

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