What is Mona.py?

• A pycommand for Immunity Debugger, designed and developed to aid the exploit development process

• Automates various tasks such as address search, pattern generation and comparison, egg hunter generation etc.

• Replaces pvefindaddr

• Developed by Corelanc0d3r (Peter Van Eeckhoutte)

• Official link: http://bit.ly/mona-py

Command 1: Set workingfolder

• Sets the working directory for mona to store command output and related files:

  • !mona config -set workingfolder c:\logs\%p

• This will tell mona to write the output to subfolders of c:\logs. The %p variable will be replaced with the process name currently being debugged.

• If you want to further group output, you can even use the %i variable in the workingfolder parameter. This variable will get replaced with the process ID of the application being debugged.

Command 2: bytearray

• Generates an array of hex bytes from \x00 to \xff (except for the excluded ones):

  • !mona bytearray

• Produces two files: text and binary

• Takes two flags:

  • -b – to exclude bytes from array

  • -r – to output array in the reverse order (\xff..\x00)

• Use compare command to automate the comparison process:

  • !mona compare –f <filename> -a <address>

Command 3: pc, po & findmsp

• Generates a cyclic pattern (Metasploit pattern) of a given size and length:

  • !mona pc <length>

• Locates given four bytes in a cyclic pattern and returns the offset:

  • !mona po <bytes>

• Find instances of the cyclic pattern:

  • !mona findmsp

• Optional argument:

  • -distance Sets the distance from ESP to begin search from

Command 4: egg

• Creates an egghunter routine with a default tag (w00t):

  • !mona egg

• Optional arguments:

  • -t : tag (ex: w00t). Default value is w00t

  • -c : enable checksum routine. Only works in conjunction with parameter -f

  • -f : file containing the shellcode

  • -depmethod : method can be “virtualprotect”, “copy” or “copy_size”

  • -depreg : sets the register that contains a pointer to the API function to bypass DEP. By default this register is set to ESI

  • -depsize : sets the size for the dep bypass routine

  • -depdest : this register points to the location of the egghunter itself.

Command 5: jmp

• Searches for pointers that will lead to execution of the code located at the address pointed by a given register:

  • !mona jmp –r <register>

• Default module criteria : skip aslr and rebase modules. The search will include OS modules by default, but this can be overruled by using the -cm os=false global option.

Command 6: seh

• Searches for pointers to routines that will lead to code execution in a SEH overwrite exploit:

  • !mona seh

• By default, it will attempt to bypass SafeSEH by excluding pointers from rebase, aslr and safeseh protected modules.

• The optional -all parameter, if specified, will also search for pointers in memory locations outside of loaded modules.

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Learn the art of exploit development

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• Hands-on Exploit Development

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• Immunity Debugger for Exploit Devs - YCSC Lab Essentials