Apr 26, 2020

How To Install Windscribe - The Best Free VPN On GNU/Linux Distros?

Why should you use Windscrive?
   Windscribe is well-known for their free VPN service but they also have a paid version. Only with a free account, you will get 10 countries to connect through and change your real IP address and 10GB of free traffic (if you use an email to sign up Windscribe), and unlimited devices.

   The Free version is awesome, but the Pro one is even better! With Pro version you will get Unlimited DataUnblock over 60 Countries and 110 CitiesConfig Generator (OpenVPN, IKEv2, SOCKS5), and full protection from R.O.B.E.R.T.

   For your information, Windscribe is one of the best VPN services in the category Free AuditValue Audit and Overall Audit in BestVPN.com Awards 2019 (Read the White Paper here). You totally can believe in Windscribe (100% no logs).

   And about R.O.B.E.R.T, it's an advanced DNS level blocker that protects you from MalwareAds and TrackersSocial trackingPornGamblingFake NewsClickbait and Cryptominers. Read more about R.O.B.E.R.T.

Anyway, Windscribe helps you:
  • Stop tracking and browse privately: Governments block content based on your location. Corporations track and sell your personal data. Get Windscribe and take back control of your privacy.
  • Unblock geo-restricted content: Windscribe masks your IP address. This gives you unrestricted and private access to entertainment, news sites, and blocked content in over 45 different countries.
  • Take your browsing history to your grave: Protect your browsing history from your network administrator, ISP, or your mom. Windscribe doesn't keep any logs, so your private data stays with you.
  • Stop leaking personal information: Prevent hackers from stealing your data while you use public WIFI and block annoying advertisers from stalking you online.
  • Go beyond basic VPN protection: For comprehensive privacy protection, use our desktop and browser combo (they're both free).

   Windscribe also supports Chrome browser, Firefox browser, Opera browser, Smart TV, Routers, Android, iOS, BlackBerry, Windows OS, Mac OS X and GNU/Linux OS, you name it.

   You can install Windscribe on Ubuntu, Debian, Fedora, CentOS, Arch Linux and their based distros too.

   But to install and safely use Internet through Windscribe, you must sign up an account first. If you already have an account then let's get started.

How to install Windscribe on Arch and Arch-based distros?
   First, open your Terminal.

   For Arch Linux and Arch-based distro users, you can install Windscribe from AUR. Run these commands without root to download and install Windscribe on your Arch:

   For other distro users, go to VPN for Linux - Windscribe choose the binary file that compatible with your distro (.DEB for Debian and Ubuntu based, .RPM for Fedora and CentOS based) and then install it.
dpkg -i [Windscribe .DEB package]
rpm -ivh [Windscribe .RPM package]

   Or you can scroll down to Pick Your Distro, click to the distro version you use, or click to the distro version that your distro is based on and follow the instructions.

   Now enter these commands to auto-start a and log in to Windscribe.

   Enter your username and password and then you can enjoy Windscribe's free VPN service.

How to use Windscribe on Linux?
   This is Windscribe list of commands (windscribe --help):
   If you want Windscribe to chooses the best location for you, use windscribe connect best.

   But if you want to choose location yourself, here is the list of Windscribe's locations:
   *Pro only
   Example, i want to connect to "Los Angeles - Dogg", i use windscribe connect Dogg.

   If you want to stop connecting through Windscribe use windscribe disconnect.

   For some reasons, you want to log out Windscribe from your device, use windscribe logout.

I hope this article is helpful for you 😃

Read more

Apr 25, 2020

What Is Brave Browser And How Does It Compares To Chrome ?

       There are more competing web browsers than ever, with many serving different niches. One example is Brave, which has an unapologetic focus on user privacy and comes with a radical reimagining of how online advertising ought to work.

Brave is based on Chromium, the open-source code that forms the basis for Google Chrome. But is it any good? And for those using Google Chrome, is it worth switching to Brave?

A Brief History of Brave

When Brendan Eich and Brian Bondy founded Brave in 2015, they wanted to address what they perceived as the biggest problem with the modern internet: intrusive advertising.

Advertising is the fuel that powers the modern internet, allowing websites and digital creatives to monetize their content without charging users for each article read or every video watched. That said, Eich and Bondy think it's got some pretty significant downsides, citing the potentially privacy-harming nature of advertising trackers, as well as the negative impact it has on the overall user experience.

Brave's first release came about amidst two significant trends, which ultimately defined the new browser.

First, the cryptocurrency revolution was in full swing. Companies and individuals alike—like the pseudonymous Satoshi Nakamoto—were creating their own decentralized cryptocurrencies, which quickly reached billion-dollar market capitalizations. Second, ad-blocking technology entered the mainstream. By the decade's halfway point, millions of people were blocking ads online across all browsers, desktop, and mobile.

Brave was one of the first browsers to include built advertisement and tracker blockers, leapfrogging the likes of Opera. It also came with its own cryptocurrency, called BAT (or Basic Attention Token), allowing users to reimburse the sites and creators they like.

Essentially, Brave wants to re-imagine how the Internet works: not just on a usability level, but on an economic level. It's an undeniably radical vision, but you wouldn't expect any less, given its founding team.

Brendan Eich is the inventor of the JavaScript programming language and co-founded the Mozilla Foundation, which created the popular Firefox web browser. He also briefly served as the foundation's CEO before resigning following a bitter controversy over his political donations. Brian Bondy is also ex-Mozilla, and spent time at education startup Khan Academy.

Beyond that, Brave is a reasonably standard browser. Like Edge, Chrome, and Opera, it's built upon the Blink rendering engine, which means webpages should work as you expect. Brave is also compatible with Chrome extensions.

To Track or Not to Track?

The Brave browser is characterized by an unapologetically pathological focus on user privacy. Its primary mechanism for delivering this is something called Brave Shields, which combines traditional tracker-blocking technology, paired with several under-the-hood browser configuration tweaks. This feature is turned on by default, although users can easily de-activate it should it cause websites to break.

As you might expect, Brave blocks trackers based on whether they appear in several public blocklists. Going beyond that, it also uses cloud-based machine learning to identify trackers that slipped through the net, in addition to browser-based heuristics.

Brave Shields also forces sites to use HTTPS, where both an encrypted and unencrypted option is available. By forcing users to use an encrypted version of a website, it makes it harder for those on your network to intercept and interfere with the content you visit. While this sounds abstract, it's more common than you think. Public Wi-Fi hotspots, like those found in airports, routinely inject their own ads into websites being visited. Although upgrading to SSL isn't a silver bullet against all security and privacy, it's a pretty significant security upgrade.

Separately from Shields, Brave also includes a built-in TOR browser. TOR allows users to circumvent local censorship — like that which occurs on a national or ISP level — by routing traffic through other computers on its decentralized network.

The tool, which was funded by the US Department of Defence, is frequently used by dissidents living under authoritarian governments to escape surveillance and censorship. Both Facebook and the BBC offer their own TOR 'onion' sites for this reason. Somewhat of a double-edged sword, it's also used by bad actors — drug dealers, hackers, and other online criminals — to operate free from the scrutiny of law enforcement.

Going Batty for BAT

As mentioned, Brave uses its own cryptocurrency, called BAT, for rewarding websites for the content they appreciate. Microtransaction-based tipping is nothing new. Flattr pioneered it almost a decade ago. What's different about BAT is both the implementation and the scale.

While Flattr used traditional fiat-based currencies (by that, I mean currencies like pounds, dollars, and euros), Flattr has its own fungible (essentially, convertible) cryptocurrency based on the Ethereum blockchain. And, as a browser with mainstream aspirations, Brave can deliver this concept to millions of people.

So, let's talk about how it works. Firstly, it's entirely optional. Users can choose to use brave without even touching the BAT micropayments system. By default, it's turned off.

If you decide to opt-in, users can purchase BAT through a cryptocurrency exchange, like Coinbase. They can also earn it by viewing "privacy-respecting" ads. Rather than traditional banner-based advertising, these present as push notifications. Users can choose to dismiss a notification or view it in full-screen.

Unlike traditional advertising networks, the calculations determining what advertisements to show you are performed on your own device. This means the advertiser isn't able to build a profile of you and your interests.

Of all advertising revenue that Brave receives, it shares 70 percent with users, keeping a 30 percent share. It's also worth noting that Brave's advertising program is only available in a handful of countries, mostly scattered across Europe and the Americas, plus Israel, India, Australia, South Africa, the Philippines, Singapore, and New Zealand.

Once you have some BAT, you can spend it. You can choose to automatically contribute to specific sites or tip creators on an ad-hoc basis. You can even tip individual tweets. When you open Twitter through your browser, Brave will automatically add a button to each post within your newsfeed. Pressing it will open a drop-down window, where you confirm your tip.

The sites accepting BAT include The GuardianThe Washington Post, and Slate, as well as popular tech publications like Android Police and The Register. Brave also plans to allow users to spend their rewards for more tangible rewards: like hotel stays, gift cards, and restaurant vouchers. At the time of publication, this system isn't yet available.

How Does Brave Compare to Google Chrome?

Google Chrome commands the majority of the browser market, with other competitors, including Brave, trailing behind. Independent figures about Brave's adoption aren't readily available. It doesn't show on NetMarketShare or W3Counter, as it uses Chrome's user-agent string. In October, however, the company behind Brave reported eight million monthly active users and 2.8 million daily active users.

While that's pocket change in the broader Internet ecosystem, it's still fairly impressive for a young company that's trying to disrupt a market dominated by a small handful of well-entrenched players, like Mozilla, Google, Microsoft, and Apple.

Brave promises to be faster and less energy-intensive than rival browsers, and it delivers on this. Scientific benchmarks, plus my own anecdotal experiences, pay testament to this. Furthermore, when you open a new tab, Brave shows you how much time you've saved by using it.

However, there are small annoyances you perhaps wouldn't get with other browsers. Functionality that comes standard in Chrome, like the ability to automatically translate webpages, is only available through plug-ins.

You also occasionally encounter webpages that force you to "drop" your shield to access it. And while this isn't Brave's fault, it does highlight the fact that a huge part of the conventional Internet isn't quite prepared to embrace its utopian vision of how content should be monetized.

A Brave New World?

Should you ditch Google Chrome for Brave? Maybe. There's a lot to appreciate about this browser. While it's generally fast, it also feels extremely polished. I appreciate the fact that it comes with both light and dark themes and the ease in which it allows users to protect their privacy from cross-site trackers.

But Brave is more than a browser. It's a statement about how the Internet should work. And while most people will agree that the pace and scale of online tracking should be rolled back, many may disagree whether cryptocurrencies are the best way to monetize content that is otherwise funded by traditional in-browser advertising. And are push notification-based advertisements on your desktop really a less irritating form of advertising?

Ultimately, the question is whether you agree with Brave's approach or not.


Continue reading

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Save Your Cloud: DoS On VMs In OpenNebula 4.6.1

This is a post about an old vulnerability that I finally found the time to blog about. It dates back to 2014, but from a technical point of view it is nevertheless interesting: An XML parser that tries to fix structural errors in a document caused a DoS problem.

All previous posts of this series focused on XSS. This time, we present a vulnerability which is connected another Cloud Management Platform: OpenNebula. This Infrastructure-as-a-Service platform started as a research project in 2005. It is used by information technology companies like IBM, Dell and Akamai as well as academic institutions and the European Space Administrations (ESA). By relying on standard Linux tools as far as possible, OpenNebula reaches a high level of customizability and flexibility in hypervisors, storage systems, and network infrastructures. OpenNebula is distributed using the Apache-2 license.

OpenNebula offers a broad variety of interfaces to control a cloud. This post focuses on Sunstone, OpenNebula's web interface (see Figure 1).

Figure 1: OpenNebula's Sunstone Interface displaying a VM's control interface

Before OpenNebula 4.6.2, Sunstone had no Cross-Site Request Forgery (CSRF) protection. This is a severe problem. Consider an attacker who lures a victim into clicking on a malicious link while being logged in at a private cloud. This enables the attacker to send arbitrary requests to the private cloud through the victims browser. However, we could find other bugs in OpenNebula that allowed us to perform much more sophisticated attacks.

Denial-of-Service on OpenNebula-VM

At its backend, OpenNebula manages VMs with XML documents. A sample for such an XML document looks like this:
OpenNebula 4.6.1 contains a bug in the sanitization of input for these XML documents: Whenever a VM's name contains an opening XML tag (but no corresponding closing one), an XML generator at the backend automatically inserts the corresponding closing tag to ensure well-formedness of the resulting document. However, the generator outputs an XML document that does not comply with the XML schema OpenNebula expects. The listing below shows the structure that is created after renaming the VM to 'My <x> VM':
   <NAME>My <x> VM</x>
The generator closes the <x> tag, but not the <NAME> tag. At the end of the document, the generator closes all opened tags including <NAME>.

OpenNebula saves the incorrectly generated XML document in a database. The next time the OpenNebula core retrieves information about that particular VM from the database the XML parser is mixed up and runs into an error because it only expects a string as name, not an XML tree. As a result, Sunstone cannot be used to control the VM anymore. The Denial-of-Service attack can only be reverted from the command line interface of OpenNebula.

This bug can be triggered by a CSRF-attack, which means that it is a valid attack against a private cloud: By luring a victim onto a maliciously crafted website while logged in into Sunstone, an attacker can make all the victim's VMs uncontrollable via Sunstone. A video of the attack can be seen here:

Top 10 Great Gifts For The Hacker In Your Life

Give gifts this holiday season that inspires your favorite hackers to make something great. Our ten top picks for gifts to make 'em smile are perfect for hackers of all styles, ages, and interests.
Holiday gift guides always struggle when faced with nailing down a list for hackers — that's because hackers are as diverse in their interests and fascinations as they are diverse in gender, color, size and everything else. Someone with a multi-focused set of curiosity and unique gifts for finding out what makes the crackable crack may seem like a daunting individual to stuff a stocking for … but don't fret. With a keen eye on the latest interests in hacker culture, we've got a gift guide that can make the hacker in your life smile as they enjoy using your gift to hack and explore throughout the coming year.
The Onion Pi-Iemhacker
Anonymity online: The Onion Pi
One of the most popular "snake oil" (fake) privacy gadgets is the so-called "Tor in a box" — a plug-and-play gadget that promises to make you anonymous online. Nearly all of these are made by clueless charlatans whose products put you at risk for privacy and security breaches. But your favorite hacker can just make or build an "Onion Pi" for $69.95, and with this free tutorial.

Attribution Dice
With Attribution Dice ($20), anyone can be a high-priced security consultant, and predict breach headlines before PR firms have a chance to feed them to reporters! With every security breach, hackers roll their eyes when headlines and PR firms roll out the same old, same old terms, methods and culprits. Instead of rolling eyes, your hacker can roll the dice, and wow friends, family, and neighbors with their hacker cyber-powers.
21 Bitcoin Computer
Money is always a welcome gift. Give the gift of going hands-on with Bitcoin with the 21 Bitcoin Computer. "The 21 Bitcoin Computer is ideal for buying and selling digital goods and services. You can use it to create bitcoin-payable APIs, set up your own personal digital goods store, pay people to share your content online, or host online games of skill." It's not cheap ($395) and comes with controversy, but it's a cool toy with a lot of potential, and 21 Inc. is going to be releasing an open source package for the device soon.
Gentleman's Bogota Lockpicks and Clear Practice Lock
Conventional wisdom suggests that all hackers know how to pick locks, but can they do it in style? A perfect stocking stuffer for slick hackers of all genders is the Gentleman's Bogota lockpick set ($34.95). These featherweights pin discreetly to a collar, hat, sleeve, vest, hemline, or wherever they choose. If the hacker you're shopping for wants to learn to lockpick, or just brush up on technique, throw in the clever Clear Practice Lock ($34.95).
Inverse Path USB Armory
In this reviewer's opinion, every hacker should have a USB Armory in their stocking this year. The Inverse Path USB Armory ($130) is a little USB stick with an entire computer onboard (800MHz ARM processor, 512MB RAM), designed to be a portable platform for personal security applications — and lives up to its reputation as "the Swiss Army Knife of security devices."
Hack-A-Day Gift Card
The cornerstone of hacker culture Hack-A-Day has a store offering gift cards and merchandise a-plenty. In it, you'll find a Bukito portable 3D printer ($899.97), ever-popular Facedancer21 and Gootfet42, a low energy Bluetooth Arduino microcontroller called the Lightblue Bean, and the pocket-sized open source robot arm, Mearm.
Hackers 20th Anniversary Blu-Ray Edition
Hack the planet! The 20th anniversary of influential 1995 cyberpunk film "Hackers" was this year, and this cult classic got a special edition Blu-ray release, making it the must-have for the hackers in your life. The 20th anniversary "Hackers" Blu-ray features an hour-long "making of" documentary, rich video and audio transfer for the film itself, and interviews with: Cast members Matthew Lillard, Fisher Stevens, and Penn Jillette; hacking consultants Nicholas Jarecki and Emmanuel Goldstein; Director Iain Softley, and many more involved with the film's production and style.
A Hacker's hope for better sleep: The Re-Timer
Hackers are increasingly hacking themselves to make their own systems run better, and one thing hackers struggle with is their sleep cycles and feeling rested. Something that can help out is the Re-Timer ($299), a retro-future looking set of glasses and kit that adjusts the circadian rhythm and suppresses the body's production of melatonin (the sleepy hormone our bodies produce which makes us feel tired). Based on 25 years of research and on the market worldwide for three years, the Re-Timer has its own jet lag calculator app, as well as its Sleep App for Fitbit that makes a customized schedule based on actual sleep tracked.
USB Rubber Ducky Deluxe and LAN Turtle
A longtime favorite with hackers, penetration testers and IT professionals, the USB Rubber Ducky Deluxe ($42.99)is a cross-platform (Windows, Mac, Linux, Android) testing and experimentation device that is detected as a keyboard — imagine the possibilities. This stocking stuffer pairs well with its animal friend LAN Turtle ($50), a covert sysadmin and pentest tool for remote access, network intel gathering, and man-in-the-middle monitoring through a simple graphic shell (all in a generic USB ethernet adapter case).
TechShop Gift Certificate
Give the gift of hacking and making: A gift certificate to a TechShop. "Part fabrication and prototyping studio, part hackerspace, and part learning center, TechShop provides access to over $1 million worth of professional equipment and software. We offer comprehensive instruction and expert staff to ensure you have a safe, meaningful and rewarding experience." There are TechShops in Arizona, California, Michigan, Missouri, Pennsylvania, Texas, and Virginia/Washington, D.C. (some states have multiple locations). Future locations include St. Louis, MO and Paris, France.
Products to avoid
If you see these products, run! You're better off with a lump of coal. Don't waste precious holiday money on "snake oil" privacy and security products like these:
  • Anonabox
  • Wemagin
  • Webcloak
  • iGuardian (now SHIELD)
  • LogMeOnce
  • Sever: The Anti-Villain Box

More info

Malicious USB Drives Infect 35,000 Computers With Crypto-Mining Botnet

Cybersecurity researchers from ESET on Thursday said they took down a portion of a malware botnet comprising at least 35,000 compromised Windows systems that attackers were secretly using to mine Monero cryptocurrency. The botnet, named "VictoryGate," has been active since May 2019, with infections mainly reported in Latin America, particularly Peru accounting for 90% of the compromised

via The Hacker NewsRelated articles

Apr 23, 2020

BurpSuite Introduction & Installation

What is BurpSuite?
Burp Suite is a Java based Web Penetration Testing framework. It has become an industry standard suite of tools used by information security professionals. Burp Suite helps you identify vulnerabilities and verify attack vectors that are affecting web applications. Because of its popularity and breadth as well as depth of features, we have created this useful page as a collection of Burp Suite knowledge and information.

In its simplest form, Burp Suite can be classified as an Interception Proxy. While browsing their target application, a penetration tester can configure their internet browser to route traffic through the Burp Suite proxy server. Burp Suite then acts as a (sort of) Man In The Middle by capturing and analyzing each request to and from the target web application so that they can be analyzed.

Everyone has their favorite security tools, but when it comes to mobile and web applications I've always found myself looking BurpSuite . It always seems to have everything I need and for folks just getting started with web application testing it can be a challenge putting all of the pieces together. I'm just going to go through the installation to paint a good picture of how to get it up quickly.

BurpSuite is freely available with everything you need to get started and when you're ready to cut the leash, the professional version has some handy tools that can make the whole process a little bit easier. I'll also go through how to install FoxyProxy which makes it much easier to change your proxy setup, but we'll get into that a little later.

Requirements and assumptions:

Mozilla Firefox 3.1 or Later Knowledge of Firefox Add-ons and installation The Java Runtime Environment installed

Download BurpSuite from http://portswigger.net/burp/download.htmland make a note of where you save it.

on for Firefox from   https://addons.mozilla.org/en-US/firefox/addon/foxyproxy-standard/

If this is your first time running the JAR file, it may take a minute or two to load, so be patient and wait.

Video for setup and installation.

You need to install compatible version of java , So that you can run BurpSuite.

Related links

Apr 22, 2020

Takeover - SubDomain TakeOver Vulnerability Scanner

Sub-domain takeover vulnerability occur when a sub-domain (subdomain.example.com) is pointing to a service (e.g: GitHub, AWS/S3,..) that has been removed or deleted. This allows an attacker to set up a page on the service that was being used and point their page to that sub-domain. For example, if subdomain.example.com was pointing to a GitHub page and the user decided to delete their GitHub page, an attacker can now create a GitHub page, add a CNAME file containing subdomain.example.com, and claim subdomain.example.com. For more information: here

# git clone https://github.com/m4ll0k/takeover.git
# cd takeover
# python takeover.py
wget -q https://raw.githubusercontent.com/m4ll0k/takeover/master/takeover.py && python takeover.py

Related word

Samurai: Web Testing Framework

"The Samurai Web Testing Framework is a live linux environment that has been pre-configured to function as a web pen-testing environment. The CD contains the best of the open source and free tools that focus on testing and attacking websites. In developing this environment, we have based our tool selection on the tools we use in our security practice. We have included the tools used in all four steps of a web pen-test." read more...

Website: http://samurai.inguardians.com

Related posts

Playing With TLS-Attacker

In the last two years, we changed the TLS-Attacker Project quite a lot but kept silent about most changes we implemented. Since we do not have so much time to keep up with the documentation (we are researchers and not developers in the end), we thought about creating a small series on some of our recent changes to the project on this blog.

We hope this gives you an idea on how to use the most recent version (TLS-Attacker 2.8). If you feel like you found a bug, don't hesitate to contact me via GitHub/Mail/Twitter. This post assumes that you have some idea what this is all about. If you have no idea, checkout the original paper from Juraj or our project on GitHub.

TLDR: TLS-Attacker is a framework which allows you to send arbitrary protocol flows.

# Install & Use Java JDK 8
$ sudo apt-get install maven
$ git clone https://github.com/RUB-NDS/TLS-Attacker
$ cd TLS-Attacker
$ mvn clean package

So, what changed since the release of the original paper in 2016? Quite a lot! We discovered that we could make the framework much more powerful by adding some new concepts to the code which I want to show you now.

Action System

In the first Version of TLS-Attacker (1.x), WorkflowTraces looked like this:
Although this design looks straight forward, it lacks flexibility. In this design, a WorkflowTrace is basically a list of messages. Each message is annotated with a <messageIssuer>, to tell TLS-Attacker that it should either try to receive this message or send it itself. If you now want to support more advanced workflows, for example for renegotiation or session resumption, TLS-Attacker will soon reach its limits. There is also a missing angle for fuzzing purposes. TLS-Attacker will by default try to use the correct parameters for the message creation, and then apply the modifications afterward. But what if we want to manipulate parameters of the connection which influence the creation of messages? This was not possible in the old version, therefore, we created our action system. With this action system, a WorkflowTrace does not only consist of a list of messages but a list of actions. The most basic actions are the Send- and ReceiveAction. These actions allow you to basically recreate the previous behavior of TLS-Attacker 1.x . Here is an example to show how the same workflow would look like in the newest TLS-Attacker version:

As you can see, the <messageIssuer> tags are gone. Instead, you now indicate with the type of action how you want to deal with the message. Another important thing: TLS-Attacker uses WorkflowTraces as an input as well as an output format. In the old version, once a WorkflowTrace was executed it was hard to see what actually happened. Especially, if you specify what messages you expect to receive. In the old version, your WorkflowTrace could change during execution. This was very confusing and we, therefore, changed the way the receiving of messages works. The ReceiveAction has a list of <expectedMessages>. You can specify what you expect the other party to do. This is mostly interesting for performance tricks (more on that in another post), but can also be used to validate that your workflow executedAsPlanned. Once you execute your ReceiveAction an additional <messages> tag will pop up in the ReceiveAction to show you what has actually been observed. Your original WorkflowTrace stays intact.

During the execution, TLS-Attacker will execute the actions one after the other. There are specific configuration options with which you can control what TLS-Attacker should do in the case of an error. By default, TLS-Attacker will never stop, and just execute whatever is next.


As you might have seen the <messageIssuer> tags are not the only thing which is missing. Additionally, the cipher suites, compression algorithms, point formats, and supported curves are missing. This is no coincidence. A big change in TLS-Attacker 2.x is the separation of the WorkflowTrace from the parameter configuration and the context. To explain how this works I have to talk about how the new TLS-Attacker version creates messages. Per default, the WorkflowTrace does not contain the actual contents of the messages. But let us step into TLS-Attackers point of view. For example, what should TLS-Attacker do with the following WorkflowTrace:

Usually, the RSAClientKeyExchange message is constructed with the public key from the received certificate message. But in this WorkflowTrace, we did not receive a certificate message yet. So what public key are we supposed to use? The previous version had "some" key hardcoded. The new version does not have these default values hardcoded but allows you as the user to define the default values for missing values, or how our own messages should be created. For this purpose, we introduced the new concept of Configs. A Config is a file/class which you can provide to TLS-Attacker in addition to a WorkflowTrace, to define how TLS-Attacker should behave, and how TLS-Attacker should create its messages (even in the absence of needed parameters). For this purpose, TLS-Attacker has a default Config, with all the known hardcoded values. It is basically a long list of possible parameters and configuration options. We chose sane values for most things, but you might have other ideas on how to do things. You can execute a WorkflowTrace with a specific config. The provided Config will then overwrite all existing default values with your specified values. If you do not specify a certain value, the default value will be used. I will get back to how Configs work, once we played a little bit with TLS-Attacker.

TLS-Attacker ships with a few example applications (found in the "apps/" folder after you built the project). While TLS-Attacker 1.x was mostly a standalone tool, we currently see TLS-Attacker more as a library which we can use by our more sophisticated projects. The current example applications are:
  • TLS-Client (A TLS-Client to execute WorkflowTraces with)
  • TLS-Server (A TLS-Server to execute WorkflowTraces with)
  • Attacks (We'll talk about this in another blog post)
  • TLS-Forensics (We'll talk about this in another blog post)
  • TLS-Mitm (We'll talk about this in another blog post)
  • TraceTool (We'll talk about this in another blog post) 


The TLS-Client is a simple TLS-Client. Per default, it executes a handshake for the default selected cipher suite (RSA). The only mandatory parameter is the server you want to connect to (-connect).

The most trivial command you can start it with is:

Note: The example tool does not like "https://" or other protocol information. Just provide a hostname and port

Depending on the host you chose your output might look like this:

or like this:

So what is going on here? Let's start with the first execution. As I already mentioned. TLS-Attacker constructs the default WorkflowTrace based on the default selected cipher suite. When you run the client, the WorkflowExecutor (part of TLS-Attacker which is responsible for the execution of a WorkflowTrace) will try to execute the handshake. For this purpose, it will first start the TCP connection.
This is what you see here:

After that, it will execute the actions specified in the default WorkflowTrace. The default WorkflowTrace looks something like this:
This is basically what you see in the console output. The first action which gets executed is the SendAction with the ClientHello.

Then, we expect to receive messages. Since we want to be an RSA handshake, we do not expect a ServerKeyExchange message, but only want a ServerHello, Certificate and a ServerHelloDone message.

We then execute the second SendAction:

and finally, we want to receive a ChangeCipherSpec and Finished Message:

In the first execution, these steps all seem to have worked. But why did they fail in the second execution? The reason is that our default Config does not only allow specify RSA cipher suites but creates ClientHello messages which also contain elliptic curve cipher suites. Depending on the server you are testing with, the server will either select and RSA cipher suite, or an elliptic curve one. This means, that the WorkflowTrace will not executeAsPlanned. The server will send an additional ECDHEServerKeyExchange. If we would look at the details of the ServerHello message we would also see that an (ephemeral) elliptic curve cipher suite is selected:

Since our WorkflowTrace is configured to send an RSAClientKeyExchange message next, it will just do that:

Note: ClientKeyExchangeMessage all have the same type field, but are implemented inside of TLS-Attacker as different messages

Since this RSAClientKeyExchange does not make a lot of sense for the server, it rejects this message with a DECODE_ERROR alert:

If we would change the Config of TLS-Attacker, we could change the way our ClientHello is constructed. If we specify only RSA cipher suites, the server has no choice but to select an RSA one (or immediately terminate the connection). We added command line flags for the most common Config changes. Let's try to change the default cipher suite to TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA:

As you can see, we now executed a complete ephemeral elliptic curve handshake. This is, because the -cipher flag changed the <defaultSelectedCiphersuite> parameter (among others) in the Config. Based on this parameter the default WorkflowTrace is constructed. If you want, you can specify multiple cipher suites at once, by seperating them with a comma.

We can do the same change by supplying TLS-Attacker with a custom Config via XML. To this we need to create a new file (I will name it config.xml) like this:

You can then load the Config with the -config flag:

For a complete reference of the supported Config options, you can check out the default_config.xml. Most Config options should be self-explanatory, for others, you might want to check where and how they are used in the code (sorry).

Now let's try to execute an arbitrary WorkflowTrace. To do this, we need to store our WorkflowTrace in a file and load it with the -workflow_input parameter. I just created the following WorkflowTrace:

As you can see I just send a ServerHello message instead of a ClientHello message at the beginning of the handshake. This should obviously never happen but let's see how the tested server reacts to this.
We can execute the workflow with the following command:

The server (correctly) responded with an UNEXPECTED_MESSAGE alert. Great!

Output parameters & Modifications

You are now familiar with the most basic concepts of TLS-Attacker, so let's dive into other things TLS-Attacker can do for you. As a TLS-Attacker user, you are sometimes interested in the actual values which are used during a WorkflowTrace execution. For this purpose, we introduced the -workflow_output flag. With this parameter, you can ask TLS-Attacker to store the executed WorkflowTrace with all its values in a file.
Let's try to execute our last created WorkflowTrace, and store the output WorkflowTrace in the file out.xml:

The resulting WorkflowTrace looks like this:

As you can see, although the input WorkflowTrace was very short, the output trace is quite noisy. TLS-Attacker will display all its intermediate values and modification points (this is where the modifiable variable concept becomes interesting). You can also execute the output workflow again.

Note that at this point there is a common misunderstanding: TLS-Attacker will reset the WorkflowTrace before it executes it again. This means, it will delete all intermediate values you see in the WorkflowTrace and recompute them dynamically. This means that if you change a value within <originalValue> tags, your changes will just be ignored. If you want to influence the values TLS-Attacker uses, you either have to manipulate the Config (as already shown) or apply modifications to TLS-Attackers ModifiableVariables. The concept of ModifiableVariables is mostly unchanged to the previous version, but we will show you how to do this real quick anyway.

So let us imagine we want to manipulate a value in the WorkflowTrace using a ModifiableVariable via XML. First, we have to select a field which we want to manipulate. I will choose the protocol version field in the ServerHello message we sent. In the WorkflowTrace this looked like this:

For historical reasons, 0x0303 means TLS 1.2. 0x0300 was SSL 3. When they introduced TLS 1.0 they chose 0x0301 and since then they just upgraded the minor version.

In order to manipulate this ModifiableVariable, we first need to know its type. In some cases it is currently non-trivial to determine the exact type, this is mostly undocumented (sorry). If you don't know the exact type of a field you currently have to look at the code. The following types and modifications are defined:
  • ModifiableBigInteger: add, explicitValue, shiftLeft, shiftRight, subtract, xor
  • ModifiableBoolean: explicitValue, toggle
  • ModifiableByteArray: delete, duplicate, explicitValue, insert, shuffle, xor
  • ModifiableInteger: add, explicitValue, shiftLeft, shiftRight, subtract, xor
  • ModifiableLong: add, explicitValue, subtract, xor
  • ModifiableByte: add, explicitValue, subtract, xor
  • ModifiableString: explicitValue
As a rule of thumb: If the value is only up to 1 byte of length we use a ModifiableByte. If the value is up to 4 bytes of length, but the values are used as a normal number (for example in length fields) it is a ModifiableInteger. Fields which are used as a number which are bigger than 4 bytes (for example a modulus) is usually a ModifiableBigInteger. Most other types are encoded as ModifiableByteArrays. The other types are very rare (we are currently working on making this whole process more transparent).
Once you have found your type you have to select a modification to apply to it. For manual analysis, the most common modifications are the XOR modification and the explicit value modification. However, during fuzzing other modifications might be useful as well. Often times you just want to flip a bit and see how the server responds, or you want to directly overwrite a value. In this example, we want to overwrite a value.
Let us force TLS-Attacker to send the version 0x3A3A. To do this I consult the ModifiableVariable README.md for the exact syntax. Since <protocolVersion> is a ModifiableByteArray I search in the ByteArray section.

I find the following snippet:

If I now want to change the value to 0x3A3A I modify my WorkflowTrace like this:

You can then execute the WorkflowTrace with:

With Wireshark you can now observe  that the protocol version got actually changed. You would also see the change if you would specify a -workflow_output or if you start the TLS-Client with the -debug flag.

More Actions

As I already hinted, TLS-Attacker has more actions to offer than just a basic Send- and ReceiveAction (50+ in total). The most useful, and easiest to understand actions are now introduced:


This action does basically what the CCS message does. It activates the currently "negotiated" parameters. If necessary values are missing in the context of the connection, they are drawn from the Config.


This action does the opposite. If the encryption was active, we now send unencrypted again.


Prints the last application data message either sent or received.


Prints the proposed extensions (from the client)


Prints the secrets (RSA) from the current connection. This includes the nonces, cipher suite, public key, modulus, premaster secret, master secret and verify data.


Resets the message digest. This is usually done if you want to perform a renegotiation.


Closes and reopens the connection. This can be useful if you want to analyze session resumption or similar things which involve more than one handshake.


Send a ClientKeyExchange message, and always chooses the correct one (depending on the current connection state). This is useful if you just don't care about the actual cipher suite and just want the handshake done.


(Maybe) sends a ServerKeyExchange message. This depends on the currently selected cipher suite. If the cipher suite requires the transmission of a ServerKeyExchange message, then a ServerKeyExchange message will be sent, otherwise, nothing is done. This is useful if you just don't care about the actual cipher suite and just want the handshake done.


This lets TLS-Attacker sleep for a specified amount of time (in ms).

As you might have already seen there is so much more to talk about in TLS-Attacker. But this should give you a rough idea of what is going on.

If you have any research ideas or need support feel free to contact us on Twitter (@ic0nz1, @jurajsomorovsky ) or at https://www.hackmanit.de/.

If TLS-Attacker helps you to find a bug in a TLS implementation, please acknowledge our tool(s). If you want to learn more about TLS, Juraj and I are also giving a Training about TLS at Ruhrsec (27.05.2019).
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