Bandit0

بسم الله الرحمن الرحيم

today we are going to solve bandit0 using python with Paramiko’s library

before we start this is paramiko’s manual

https://www.paramiko.org/

to install Paramiko let us issue

python3 -m pip install paramiko

if you are using windows or you need to read more about how to install packages within python check python documentation

https://packaging.python.org/en/latest/tutorials/installing-packages/

bandit0

import paramiko , time #1

ssh = paramiko.SSHClient() #2

ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy()) #3

ssh.connect(hostname='bandit.labs.overthewire.org',port=2220,username='bandit0',password='bandit0') #4

print("CONNECTED") #5

stdin ,stdout,stderr = ssh.exec_command("cat readme ") #6

time.sleep(5) #7

#print(f'Input: {stdin.read().decode("utf8")}') #8
print(f'flag: {stdout.read().decode("utf8")}') #9
print(f'Error: {stderr.read().decode("utf8")}') #10

#stdin.close() #11
stdout.close() #12
stderr.close() #13

ssh.close() #14

#1

we import the two libraries we are going to use (paramiko & time)

library time is important you will see below

#2

we import an object calls SSHClient to initialize our SSH connection

#3

we add the policy → AutoAddPolicy

because we do not have SSH host key

host-key: A public key used for authenticating a host in the SSH protocol to hosts that want to communicate with it

also we can write these #1,2,3 lines of codes as following

from paramiko import SSHClient , AutoAddPolicy 
import time 
ssh = SSHClient()

ssh.set_missing_host_key_policy(AutoAddPolicy())

#4

we define the connection hostname, port,username,password

#5

we are just making sure the connection is established

#6

we define the command we want to execute ,and we put the result in three parameters

stdin → standard input, for the input whether command ,txt ,etc ..

stdout → standard output, for output in another word the result of the command executed

stderr → standard error , for the errors if you get one while executing the command

#7

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we wait for 5 seconds after executing the commands and before finishing the session

#8 ,11

actually there is no need for standard input

#9

we read what we got from standard output

#10

in this line we will read the error if we got one

#12 ,13

we close standard input and error because we finished working with them

#14

we are closing the SSH session

NOTES

1-

if we did not define time after executing the commands and before finishing the session we will get error

2-

we have to write the standards as following

stdin ,stdout,stderr = ssh.exec_command("cat readme ") #6

Standard input, then standard output, then standard error

if we remove one of then we will get error

some one may ask hummmmmmm so is it possible to change there position i will answer yeah even you can change their name .

python do not understand their name but he know that the first position is the stdin and the second position is stdout and the third position is stderr

so one can write it for instance

input ,output ,error

and if we write it like that

stderr, stdin,stdout

python will consider stderr as standard input

and stdin as standard output

and stdout as standard error