Download OB 1

[mateuszk87]

I am trying to upload OB 1 from the PLC and then downloading the same code to the same PLC (also OB 1). Unfortunately it is not working or I did not understand the full upload and download functions :( (I am using python-snap7)

#Uploading code from PLC
poe_block = self.client.full_upload("OB", 1)
block_size = poe_block[1]
total_code = poe_block[0][:block_size] #take only block size amount of bytes

#now the same code is downloaded again
self.client.download(data=total_code, block_num=1)

#My console output:

INFO:snap7.client:creating snap7 client
INFO:snap7.client:connecting to 192.168.200.199:102 rack 0 slot 0
DEBUG:snap7.client:setting param number 2 to 102
DEBUG:snap7.common:error text for 0x1b00000
ERROR:snap7.common:CPU : block insert refused
Traceback (most recent call last):
  File "/Users/mateusz/ics_payload_generator/fusabot/test.py", line 12, in 
    print attacker.upload_mc7_code('/Users/mateusz/ics_payload_generator/showcase/current3.mc7', 1)
  File "/Users/mateusz/ics_payload_generator/fusabot/attacks/attacker.py", line 76, in upload_mc7_code
    return self.client.download(data=mc7_block, block_num=block_number)
  File "/usr/local/Cellar/python/2.7.8/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/snap7/client.py", line 21, in f
    check_error(code, context="client")
  File "/usr/local/Cellar/python/2.7.8/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/snap7/common.py", line 65, in check_error
    raise Snap7Exception(error)
snap7.snap7exceptions.Snap7Exception: CPU : block insert refused

[Davide Nardella]

Why are you connecting with Rack=0 and slot=0, is it a S71200/1500 ?

[mateuszk87]

Thanks for your fast reply.

Good point! I changed it to rack=0, slot=2 (S7-300)

INFO:snap7.client:creating snap7 client
INFO:snap7.client:connecting to 192.168.200.199:102 rack 0 slot 2
DEBUG:snap7.client:setting param number 2 to 102

Still I get the same error :(

EBUG:snap7.common:error text for 0x1b00000
ERROR:snap7.common:CPU : block insert refused

[Davide Nardella]

All errors of type "CPU : blablabla" come directly from the PLC.

This error means that the download sequence was accomplished but the CPU refused the Block insertion.

This can happen if the cpu selector is on "run" (instead of "run/p" or "Stop") or because there is a protection level set.

Try to run ClientDemo (from rich-demos/<your platform=""> folder) and look at the group "security".