Posts Tagged ‘personal privacy’

Howto Pass SSH traffic through a Secured Corporate Proxy server with corkscrew, using sshd as a standalone proxy service with no proxy installed on remote Linux server or VPS

Tuesday, November 19th, 2019

howto pass ssh traffic through proxy to remote server use remote machine as a proxy for connecting to the Internet

Working in the big bad corporate world (being employed in  any of the Fortune 500) companies, especially in an IT delivery company is a nasty thing in terms of User Personal Data Privacy because usually when employeed in any of a corporation, the company ships you with a personal Computer with some kind of pre-installed OS (most often this is Windows) and the computer is not a standalone one but joined in Active Directory (AD) belonging to Windows Domain and centrally administered by whoever.

As part of the default deplyed configuration in this pre-installed OS and software is that part or all your network traffic and files is being monitored in some kind of manner as your pre-installed Windows or Linux notebook given by the Corporation is having a set of standard software running in the background, and even though you have Windows Administrator there are many things you have zero control or even if you have changed it once the Domain Policy is triggered your custom made changes / Installed Programs that happen to be against the company policy are being automatically deleted, any registry changes made are being rewinded etc. Sometimes even by trying to manually clean up your PC from the corporate crapware,  you might breaks access to the corporate DMZ firewalled network. A common way to secure their employee PC data large companies have a Network seperation, your PC when not connected to the Corporate VPN is having a certain IP configuration and once connected to the Demilitarized Zone VPN those configuration changes and the PC have access to internal company infrastructure servers / router / switches / firewalls / SANs etc. Access to corporate Infrastructure is handled via crypted VPN clinet such as Cisco AnyConnect Secure Mobility Client which is perhaps one of the most used ones out there.

Part of the common software installed to Monitor your PC for threats / viruses / trojans among which is MCafee / EMET (Enhandced Mitigation Experience Toolkit) the PC is often prebundled with some kind of anti-malware (crapware) :). But the tip of the iceberg on user surveillance where most of surveillance happens is the default installed proxy on the PC which usually does keep track of all your remote accessed HTTP Website URLs accessed in plain text – traffic flowing on Port 80 and crypted one on standard (SSL) Port 443. This Web Traffic is handled by the Central Corporate proxy that is being deployed via some kind of Domain policy, every time the Computer joins the Windows domain. 

This of course is a terrible thing for your Browsing security and together with the good security practice to run your browser in Incognito mode, which makes all your browsing activity such as access URLs History or Saved Cookies data to be cleared up on a Browser close it is important to make sure you run your own personal traffic via a separate browser which you will use only for your own concern browsing such as Accessing your Bank Money Accounts to check your Monthly Sallary / Purchase things online via /, whether all of the rest traffic company related is trafficed via the default set corporate central proxy.
This is relatively easy sometimes in companies, where security is not of a top concern but in corporations with tightened security accessing remote proxy, or accessing even common daily news and Public Email websites or social media sites / Twitter / Youtube will be filtered so the only way to reach them will be via some kind of Proxy and often this proxy is the only way out to the Free world from the corporate jail.

Here is where the good old SSH comes as a saving grace as it turns out SSH traffic could be trafficed over a proxy. In below article I will give you a short insight on how Proxy through SSH could be achieved to Secure your dailty web traffic and use SSH to reach your own server on the Internet as well as how you can copy securely data via SSH through corporate Proxy. 

1. How to view your corporate used (default) proxy / Check Proxy.pac file definitions


To get an idea what is the used proxy on your Corporate PC (as most corporate employee given notebooks are running some kind of M$ Windows)  you can go to:

Windows Control Panel -> Internet Options -> Connections -> Lan Settings


Under the field Proxy server (check out the Proxy configured Address and Port number )


Having that as browsers venerate the so-called Proxy.pac file, to be rawly aware on some general Company Proxy configured definitions you can access in a browser the proxy itself fething the proxy.pac file for example.




This is helpful as some companies Proxies have some proxy rules that reveal some things about its Internet architecture and even some have some badly configured proxy.pac files which could be used to fool the proxy under some circumstances 🙂

2. Few of the reasons corporations proxy all their employee's work PC web traffic


The corporate proxying of traffic has a number of goals, some of which are good hearted and others are for mostly spying on the users.


1. Protect Corporate Employees from malicious Viruses / Trojans Horses / Malware / Badware / Whatever ware – EXCELLENT
2. Prevent users from acessing a set of sources that due to the corporate policy are considered harmful (e.g. certain addresses 
of information or disinformation of competitors, any Internet source that might preach against the corporation, hacking ralated websites etc.) – NOT GOOD (for the employee / user) and GOOD for the company
3.Spy on the users activity and be able to have evidence against the employee in case he decided to do anything harmful to the company evidences from proxy could even later be used in court if some kind of corpoate infringment occurs due to misbehave of the employee. – PERFECT FOR COMPANY and Complete breach of User privacy and IMHO totally against European Union privacy legislation such as GDRP
4. In companies that are into the field of Aritificial Intelligence / Users behavior could even be used to advance Self-learning bots and mechanisms – NASTY ! YAECKES


3. Run SSH Socks proxy to remote SSHd server running on common SSL 443 port


Luckily sysadmins who were ordered the big bosses to sniff on your Web behaviour and preferences could be outsmarted with some hacks.

To protect your Browsing behaviours and Secure your privacy perhaps the best option is to use the Old but gold practice o Securing your Networkf traffic using SSH Over Proxy and SSH Dynamic tunnel as a Proxy as explained in my previous article here.


In short the quest way to have your free of charge SOCKS  Remote proxy to your Home based Linux installed OS server / VPN with a Public Internet address is to use ssh as so:


ssh -D 3128 UserName@IP-of-Remote-SSHD-Host -p 443


This will start the SOCKS Proxy tunnel from Corporate Work PC to your Own Home brew server.

For some convenience it is useful to set up an .alias (for cygwin) / linux users in .bashrc file:


alias proxy='ssh -D 3128 UserName@IP-of-Remote-SSHD-Host -p 443';


To start using the Proxy from browser, I use a plugin called FoxyProxy in Chrome and Firefox browsers
set-up to connect to localhost – for All Protocols as a SOCKs v5 Proxy.

The sshd Socks proxy can be used for multiple others for example, using it you can also pass on traffic from Mail client such as Thunderbird to your Email server if you're behind a firewall prohibiting access to the common POP3 port 110 or IMAP port TCP 143. 

4. How to access SSH through Proxy using jumphost SSH hop

If you're like me and you have on your Home Linux machine only one Internet address and you have already setupped an SSL enabled service (lets say Webmail) to listen to that Public Internet IP and you don't have the possibility to run another instance of /usr/bin/sshd on port 443 via configuration or manually one time by issuing:


/usr/sbin/sshd -p 443


Then you can use another ssh another Linux server as a jump host to your own home Linux sshd server. This can be done even by purchasing a cheap VPS server for lets say 3 dollars month etc. or even better if you have a friend with another Linux home server, you can ask him to run you sshd on TCP port 443 and add you an ssh account.
Once you have the second Linux machine as JumpHost to reach out to your own machine use:


ssh -J -v


To easify this a bit long line it is handy to use some kind of alias like:


alias sshhome='ssh -J -v'


The advantage here is just by issuing this sshd tunnel and keeping it open in a terminal or setting it up as Plink Putty tunnel you have all your Web Traffic Secured
between your Work Corporate PC and your Home Brew Server, keeping the curious eyes of your Company Security Officers from your own Web traffic, hence
separating the corporate privacy from your own personal privacy. Using the just established own SSH Proxy Tunnel to home for your non-work stuff browsing habits
from the corporate systems which are accessed by switching with a button click in FoxyProxy to default proxy settings.

5. How to get around paranoid corporate setup where only remote access to Corporate proxy on TCP Port 80 and TCP 443 is available in Browser only


Using straight ssh and to create Proxy will work in most of the cases but it requires SSH access to your remote SSH running server / VPS on TCP Port 22, however under some Fort-Nox like financial involved institutions and companies for the sake of tightened security, it is common that all Outbound TCP Ports are prohibited except TCP Port 80 and SSL 443 as prior said, so what can you do then to get around this badful firewall and access the Internet via your own server Proxy? 
The hack to run SSH server either on tcp port 80 or tcp port 443 on remote Host and use 443 / 80 to acess SSHD should work, but then even for the most paranoid corporations the ones who are PCI Compliant – PCI stands for (Payment Card Industry), e.g. works with Debit and Credit Card data etc, accessing even 80 or 443  ports with something like telnet client or netcat will be impossible. 
Once connected to the corporate VPN,  this 2 two ports firewall exceptions will be only accessible via the Corporate Proxy server defined in a Web Browser (Firefox / IE / Chrome etc.) as prior explained in article.

The remedy here is to use a 3rd party tools such as httptunnel or corkscrew that  are able to TUNNEL SSH TRAFFIC VIA CORPORATE PROXY SERVER and access your own resource out of the DMZ.

Both httptunnel and corkscrew are installable both on most Linux distros or for Windows users via CygWin for those who use MobaXterm.

Just to give you better idea on what corkscrew and (hts) httptunnel does, here is Debian packages descriptions.

# apt-cache show​ corkscrew
" corkscrew is a simple tool to tunnel TCP connections through an HTTP
 proxy supporting the CONNECT method. It reads stdin and writes to
 stdout during the connection, just like netcat.
 It can be used for instance to connect to an SSH server running on
 a remote 443 port through a strict HTTPS proxy.


# apt-cache show httptunnel|grep -i description -A 7
Description-en: Tunnels a data stream in HTTP requests
 Creates a bidirectional virtual data stream tunnelled in
 HTTP requests. The requests can be sent via a HTTP proxy
 if so desired.
 This can be useful for users behind restrictive firewalls. If WWW
 access is allowed through a HTTP proxy, it's possible to use
 httptunnel and, say, telnet or PPP to connect to a computer

Description-md5: ed96b7d53407ae311a6c5ef2eb229c3f
Tag: implemented-in::c, interface::commandline, interface::daemon,
 network::client, network::server, network::vpn, protocol::http,
 role::program, suite::gnu, use::routing
Section: net
Priority: optional
Filename: pool/main/h/httptunnel/httptunnel_3.3+dfsg-4_amd64.deb

Windows cygwin users can install the tools with:

apt-cyg install –yes corkscrew httptunnel

Linux users respectively with:

apt-get install –yes corkscrew httptunnel


yum install -y corkscrew httptunnel


You will then need to have the following configuration in your user home directory $HOME/.ssh/config file

ProxyCommand /usr/bin/corkscrew your-corporate-firewall-rpoxy-url 8080 %h %p



Picture Copyright by Daniel Haxx

The best picture on how ssh traffic is proxied is the one found on Daniel Haxx's website which is a great quick tutorial which originally helped to get the idea of how corkscrew works in proxying traffic I warmly recommend you take a quick look at his SSH Through or over Proxy article. could be also and IP if you don't have your own domain name in case if using via some cheap VPN Linux server with SSH, or alternatively
if you don't want to spend money on buying domain for SSH server (assuming you don't have such yet) you can use Dyn DNS or NoIP.

Another thing is to setup the proper http_proxy / https_proxy / ftp_proxy variable exports in $HOME/.bashrc in my setup I have the following:

export ftp_proxy="http://your-corporate-firewall-rpoxy-url:8080"
export https_proxy="https://your-corporate-firewall-rpoxy-url:8080"
export http_proxy="http://your-corporate-firewall-rpoxy-url:8080"
export HTTP_PROXY="http://your-corporate-firewall-rpoxy-url:8080"
export HTTPS_PROXY="http://your-corporate-firewall-rpoxy-url:8080"


6. How to Transfer Files / Data via SSH Protocol through  Proxy with SCP and SFTP

Next logical question is how to Transfer your own personal encrypted files (that contains no corporate sensitive information) between your Work laptop and home brew Linux ssh server or cheap VPN.

It took me quite a lot of try-outs until finally I got it how Secure Copy (scp) command can be used toto transfer files between my Work Computer and my Home brew server using JumpHost, here is how:

scp -o 'ProxyJump' ~/file-or-files-to-copy*

I love using sftp (Secure FTP) command Linux client to copy files and rarely use scp so I have a lot of try-outs to connect interacitvely via the Corporate Proxy server over a Jump-Host:443 to my Destination home machine, 


I've tried using netcat as it was pointed in many articles online, like so to traffic my sftp traffic via my localhost binded SSH Socks proxy on :3128 together with netcat as shown in article prior example, using following line:

sftp -oProxyCommand='/bin/nc -X connect -x %h %p' 22


Also tried proxy connect like this:


sftp -o ProxyCommand="proxy-connect -h localhost -p 3128 %h %p"


Moreover, tried to use the ssh  command (-s) argument capability to invoke SSH protocol subsystem feature which is used to facilitiate use of SSH secure transport for other application

ssh -v -J hipo@Jump-Host:443 -s sftp -v

open failed: administratively prohibited: open failed


Finally decided to give a try to the same options arguments as in scp and thanks God it worked and I can even access via the Corporate Proxy through the Jump Host SSH interactively via Secure FTP 🙂


sftp -o 'ProxyJump'

To save time from typing this long line every time, I've setup the following alias to ~/.bashrc

alias sftphome='sftp -o 'ProxyJump''



Of course using own Proxy via your Home brew SSH Machine as well as transferring your data securely from your Work PC (notebook) to Home does not completely make you Surveillance free, as the Corporate Windows installed OS image is perhaps prebundled with its own integrated Keylogger as well as the Windows Domain administrators have certainly access to connect to your PC and run various commands, so this kind of Security is just an attempt to make company has less control and know less on your browsing habits and the best solution where possible to secure your privacy and separate your Personal Space form Work space by using a second computer (if having the ability to work from home) with a KVM Switch device and switch over your Work PC and Home PC via it or in some cases (where companies) allows it, setup something like VNC server (TightVNC / RealVNC) on work PC and leave it all time running in office and connect remotely with vncviewer from your own controlled secured computer.

In article I've explained shortly common scenario found in corporate Work computers proxy setup, designed to Surveil all your move, mentioned few common softwares running by default to protect from Viruses and aimed to Protect user from malicious hacking tools, explained how to view your work notebook configured Proxy, shortly mentioned on Proxy.pac and hinted how to view proxy.pac config as well as gave few of the reasons why all web traffic is being routed over central proxy.

That's all folks, Enjoy the Freedom to be less surveilled !

Richard Stallman explaining Why IPads and Cell Phones are bad for freedom

Wednesday, July 11th, 2012

It is a public secret that Mobile Phones which does us very good and generally makes our daily lifes way easier are also a big enemy to our natural ihnibited freedom. Life has become such that it is almost inevitable to do any business or do a daily simple jobs without using Mobile Phone. There is almost none practically today that has wilfully rejected to use the mobile phone on any basis, almost anyone except some strangers like Richard Stallman and probably few others security freaks.

I've been shocked to find out the Father of Free Software (Richard Mathew Stallman), well known in the hacker dome as RMS does not own and didn't use any mobiles. The concerns he pointed are very much logical and rightful. Owning a mobile is a great security hole in personal privacy (mobile phones can be easily sniffed by Mobile Operators) as well as anyone wearing a mobile can be tracked up to 5 to 2 meters to the exact location where he is based on the mobile phone cells to which the mobile is connected.

Many people are not aware actually of the severeness of the issue of constant tracking of people everywhere through this call "goodies". Many mobile operators are already running a software which is building place behaviour patterns of every user of their mobile network. In other words, as we're used to bring and use the mobile everywhere in automated program is creating a map for each number assigned in some of the mobile operators. The gathered data about our location going habits can then be easily used as a indicator for predicting our future behaviour, bying habits (how many times we go to super-market), how many times we go to cinema, what kind of interests we hold etc. etc.
This combined with Google, account monitoring could possibly create a system similar to the old movies Big Brother, where all people goods and even attitudes or desires is monitored, influenced and controlled ….

The severeness of the future implications of this constant "personal surveillance and tracking device" as Stallman use to call it is very dangerous for our freedoms.

I tried to live without a mobile phone, just like Stallman for about months, and to tell you the truth the world around seems completely different when you decide not to use 'em. The time I lived wihtout a mobile, clearly show me we have come to the point we cannot any more live without GSM. We fall the trap of dependanding the little "talk box" communication for absolutely everything, obviously sacrificing privacy and freedom for convenience.
Mobiles are just one side of the coin, as the non-free software which is ruling the software market and the use of computers puts another treat and takes away many foundamential freedoms we used to have in the less technological world.

Apple as a vendor of software and hardware also denies and breaks our freedom very badly, as the company tracks everyone who owns anything created by apple connected to the internet. Besides that non-free software producers, could change the user software with a press of a button giving them the opportunity to decide what is good and bad for us, leaving us at a state of a helpless dependable users.

The topic of technological little-by-little enslavement, we're going through nowdays and the denying freedoms, we experience while being convinced by companies that we became more free by each next mambo-jambo gadget or by owning the latest smart-phone is very huge and complex but unfortunately underseen in society. I don't understand why, is it due to the low technical skills of mass users is it due to a "not-care what will happen in future" attitude, but obviously people openly discussing or protesting the technologization taking away our freedom is almost zero ….

Here is the video I found in youtube in which Stallman is asked few, questions on Ipads (IBADS) and Mobile Phone use. I believe his short explanation synthesizes the problem quite well ;;;;

I just wonder after you check the video, Would you still accept an Ipad as a birthday gift ? 🙂
Do you still think cell-phones are "good" freedom safe and reliable ?