Given a string in python, how would i split at nth byte, and perform an action with each chunk automatically?

Question

buf = "\x31\xc0\x50\x68\x2f\x2f\x73\x68\x68\x2f\x62\x69\x6e\x89\xe3\x50\x53\x89\xe1\xb0\x0b\xcd\x80";

Given this shellcode string (just an example), I would like to split into multiple chunks of nth size.

Once its been split, given unknown nth number of chunks, i would then like it to automatically perform an fuction such as

os.system("echo " + chunk[1] + ">>/tmp/final")
os.system("echo " + chunk[2] + ">>/tmp/final")

but, without specifying each action each time, and not knowing the number of chunks that its been split into

are you planning to encode and decode it into bytearray, or do you just want to divide the string at every n characters? — v.coder, Sep 25 '17 at 15:44
Just want to divide the string at every nth character, then have complete an action with how ever many unknown chunks repeatedly, as my example. — walkamile, Sep 26 '17 at 18:53
This is a nice way: https://stackoverflow.com/a/9475538/15890 — Tom Viner, Sep 26 '17 at 19:03

v.coder · Accepted Answer · 2017-09-26T19:12:42.913

1

See if the below code helps you, it divides the string at every nth character:

nbuf = [buf[i:i+n] for i in range(0, len(buf), n)]
for st in nbuf:
    cmdk = 'os.system("echo "' + st + '">>/tmp/final")'
    subprocess.call(cmdk,shell=True)

edited Sep 26 '17 at 19:12

answered Sep 26 '17 at 18:58

v.coder

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Don't loop over the indexes (you're missing a `range` for that anyway), just loop over the chunks directly. – Tom Viner Sep 26 '17 at 19:02
Thanks for the comment added the changes – v.coder Sep 26 '17 at 19:14

Given a string in python, how would i split at nth byte, and perform an action with each chunk automatically?

1 Answers1