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DoS Exploitation of Allen-Bradley's Legacy Protocol (PCCC)

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DoS Exploitation of Allen-Bradley's Legacy Protocol (PCCC)



A remote, unauthenticated attacker could send a single, specially crafted Programmable Controller Communication Commands (PCCC) packet to the controller that could potentially cause the controller to enter a DoS condition. MicroLogix 1100 controllers are affected: 1763-L16BWA, 1763-L16AWA, 1763-L16BBB, and 1763-L16DWD. CVE-2017-7924 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned.


  • José Diogo Monteiro <jdlopes@student.dei.uc.pt>
  • Luis Rosa <lmrosa@dei.uc.pt>
  • Miguel Borges de Freitas <miguelbf@dei.uc.pt>


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/dos/scada/allen_bradley_pccc
msf auxiliary(allen_bradley_pccc) > show actions
msf auxiliary(allen_bradley_pccc) > set ACTION < action-name >
msf auxiliary(allen_bradley_pccc) > show options
    ...show and set options...
msf auxiliary(allen_bradley_pccc) > run 

Time is precious, so I don’t want to do something manually that I can automate. Leveraging the Metasploit Framework when automating any task keeps us from having to re-create the wheel as we can use the existing libraries and focus our efforts where it matters.

– Jim O’Gorman | President, Offensive Security