DC30_Workshop

DEF CON 30 Workshop Mainframe Container

The scripts here are used to build the MVS 3.8j virtual mainframe for the DEFCON 30 workshop.

Thank you for taking a look at the DEFCON 30 Mainframe Buffer Overflow workshop.

Use docker

This docker container has everything you need to learn how to do MVS buffer overflows!

To start the class run the container and go to http://localhost:8080

To run the container use the below commands, make sure to change $(pwd)/docker to a folder for your system. The $(pwd) puts the docker volumes in your current working folder.

Minimal Container

Use this command if you just want to run it self contained. :warning: If you remove and relaunch the container you will lose any and all changes you made to the mainframe environment.

docker run -d \
  --name=defcon30 \
  -e HUSER=defcon \
  -e HPASS=defcon \
  -p 2323:3223 \
  -p 8888:8888 \
  -p 2121-2141:2121-2141 \
  -p 8443:8443 \
  -p 8080:8080 \
  -p 31337-31347:31337-31347 \
  -v ~/dumps:/printers \
  --restart unless-stopped \
  mainframed767/defcon30:latest

Ports explained:

• 2323: 3270 server port
• 8443: Web based tn3270 client, the secret is D3FC0N
• 8888: Hercules console web server. Username/password: defcon
• 8080: The workshop instructions
• 2121-2141 & 31337-31347: Range of web ports for FTP server

Python scripts mentioned can be found here: https://github.com/mainframed/DC30_Workshop/tree/main/extra

Expert Container

This exposes more ports and allows you to have volumes with permanence. Gives access to the hercules and MVS consoles, the card readers/writers, etc.

docker run -d \
  --name=defcon30 \
  -e HUSER=docker \
  -e HPASS=docker \
  -p 3221:3221 \
  -p 2323:3223 \
  -p 3270:3270 \
  -p 3505:3505 \
  -p 3506:3506 \
  -p 8888:8888 \
  -p 2121:2121 \
  -p 8443:8443 \
  -p 8080:8080 \
  -p 31337-31347:31337-31347 \
  -v $(pwd)/docker/config:/config \
  -v $(pwd)/docker/printers:/printers \
  -v $(pwd)/docker/punchcards:/punchcards \
  -v $(pwd)/docker/logs:/logs \
  -v $(pwd)/docker/dasd:/dasd \
  -v $(pwd)/docker/certs:/certs \
  --restart unless-stopped \
  mainframed767/defcon30:latest

Ports

Port	Description
2323	TLS Encrypted TN3270 Server Port
3270	Unencrypted TN3270 Server Port
3221	Encrypted FTPD server
2121	Unencrypted FTP Server Port
8443	Web based 3270 client which auto connects to lab mainframe https://localhost:8443
8080	The class Wiki https://localhost:8080
8888	Hercules Web Server/MVS Console. User/pass = docker
3505	Punch card reader. Converts ASCII to EBCDIC.
3506	Punch card reader. Only accepts EBCDIC files.
31337-32337	FTP Server passive port range

Volumes

Folder	Description
/config	Contains the Hercules and web3270 config files
/printers	Contains the output of the printers on CLASS=A
/punchcards	Contains the output of the puncard writer on CLASS=B
/logs	Contains Hercules logs
/dasd	Contains the MVS/CE disk images
/certs	Contains the certificates used for TLS encryption

Users

Username	Password	Description
IBMUSER	SYS1	Adminstrative User with access to everything
MVSCE01	CUL8TR	Adminstrative User with access to everything
MVSCE02	PASS4U	Generic User
DC0	DC0	DEFCON Workshop User
DC1	DC1	DEFCON Workshop User
DC2	DC2	DEFCON Workshop User
DC3	DC3	DEFCON Workshop User
DC4	DC4	DEFCON Workshop User
DC5	DC5	DEFCON Workshop User
DC6	DC6	DEFCON Workshop User
DC7	DC7	DEFCON Workshop User
DC8	DC8	DEFCON Workshop User
DC9	DC9	DEFCON Workshop User
DC10	DC10	DEFCON Workshop User
DC11	DC11	DEFCON Workshop User
DC12	DC12	DEFCON Workshop User
DC13	DC13	DEFCON Workshop User
DC14	DC14	DEFCON Workshop User
DC15	DC15	DEFCON Workshop User
DC16	DC16	DEFCON Workshop User
DC17	DC17	DEFCON Workshop User
DC18	DC18	DEFCON Workshop User
DC19	DC19	DEFCON Workshop User
DC20	DC20	DEFCON Workshop User
DC21	DC21	DEFCON Workshop User
DC22	DC22	DEFCON Workshop User
DC23	DC23	DEFCON Workshop User

:warning: With the current setup the maximum number of concurrent users is 24. If a 25th user logs on you get the following error message IKT00203I ADDRESS SPACE CREATION FAILED.

Building from scratch

• Download the most recent version of MVSCE from https://github.com/MVS-sysgen/sysgen/releases
• Copy the vulnerable FTPD server to MVP: cp extra/FTPD.MVP MVSCE/MVP/packages
• Launch MVSCE
• Submit the job MACLFTPF.jcl: cat jcl/MACLFTPF.jcl|ncat --send-only -w1 127.0.0.1 3505
• Submit the job logon_screen.jcl: cat jcl/logon_screen.jcl|ncat --send-only -w1 127.0.0.1 3505
• Submit the job terminal.jcl: cat terminal.jcl|ncat --send-only -w1 127.0.0.1 3505
• Clone the ARBAUTH repo: git clone https://github.com/jake-mainframe/ARBAUTH
• Run the python script upload.py: ./upload.py motd.txt
• Submit the job upload.jcl: cat upload.jcl|ncat --send-only -w1 127.0.0.1 3505
• Install https://github.com/mvslovers/rdrprep on your Linux box
• Clone https://github.com/mvslovers/jcc to this folder
• Install wine and wine 32: sudo apt install wine wine32
• Compile GETSPLOIT/hello.c:
  • wine ./jcc/jcc.exe -I./jcc/include -o ./GETSPLOIT/hello.c
  • ./jcc/prelink -s ./jcc/objs hello.load hello.obj
• Copy hello.load to ./GETSPLOIT: cp hello.load GETSPLOIT
• Run usersjcl.py: ./usersjcl.py
• Convert each job in the users folder with rdrprep and submit them one by one:
  • for i in *.jcl; do echo $i;rdrprep $i;cat reader.jcl|ncat --send-only -w1 172.17.0.3 3506; read; done
  • You can check the output of MVSCE printers/prt00e.txt to see each job completed
• Shutdown MVS/CE
• Re-IPL MVS/CE and enjoy your lab environment
• Then download web3270 from https://github.com/MVS-sysgen/web3270
• Follow the instructions on how to prepare for web3270
• Edit web3270.ini as appropriate
• Launch web3270 with python3 -u ./server.py --config /path/to/config --certs /path/to/certs

Files

• GETSPLOIT/hello.c vulnerable C program from https://github.com/jake-mainframe/GETSPLOIT
• ARBAUTH from https://github.com/jake-mainframe/ARBAUTH
• EBCDIC files overflows/LGBT400, overflows/LOC400, overflows/WTO400
• Dockerfile used to build docker image
• MACLFTPD.jcl: JCL file to install MACLIBS and FTPD server using MVP
• logon_screen.ans/jcl/logon_screen.jcl: ANSI/JCL to replace the NETSOL logon screen
• upload.py generates JCL used to provision datasets, copy files and get the system ready
• jcl/terminals.jcl adds 32 new terminal interfaces and updates VTAM config
• usersjcl.py creates DC00.jcl through DC23.jcl in the ./users folder
• automation.py a MVS automation python script used to deploy to docker
• matrix.txt Follow the white rabbit
• rexx/DEBRUIJN.rex: REXX script to generate de Bruijn pattern
• rexx/decodei.rex: decodes MVS hex instructions to human readeable
• motd.txt the CLIST run at logon to TSO
• mvs.sh the container run script to launch web3270, hercules