What is Man-In-The-Middle Attack (MITM) – Prevention

Protecting our data online is never going to be an easy task, especially nowadays when attackers are regularly inventing some new techniques and exploits to steal your data. Sometimes their attacks will not be so harmful for individual users. But large-scale attacks on some popular websites or financial databases could be highly dangerous. In most cases, the attackers first try to push some malware on to user’s machine. Sometimes this technique doesn’t work out, however.

Man-in-the-middle attack

Image source: Kaspersky.

What is Man-In-The-Middle Attack

A popular method is Man-In-The-Middle attack. It is also known as a bucket brigade attack, or sometimes Janus attack in cryptography. As its name suggests, the attacker keeps himself/herself between two parties, making them believe that they are talking directly to each other over a private connection, when actually the entire conversation is being controlled by the attacker.

A man-in-the-middle attack can be successful only when the attacker forms a mutual authentication between two parties. Most cryptographic protocols always provide some form of endpoint authentication, specifically to block MITM attacks on users. Secure Sockets Layer (SSL) protocol is always being used to authenticate one or both parties using a mutually trusted certification authority.

How it works

Let’s say there are three characters in this story: Mike, Rob, and Alex. Mike wants to communicate with Rob. Meanwhile, Alex (attacker) inhibit the conversation to eavesdrop and carry on a false conversation with Rob, behalf on Mike. First, Mike asks Rob for his public key. If Rob provides his key to Mike, Alex intercepts, and this is how “man-in-the-middle attack” begins. Alex then sends a forged message to Mike that claims to be from Rob but including Alex’s public key. Mike easily believes that the received key does belong to Rob when that’s not true. Mike innocently encrypts his message with Alex’s key and sends the converted message back to Rob.

In the most common MITM attacks, attacker mostly uses a WiFi router to intercept user’s communication. This technique can be work out by exploiting a router with some malicious programs to intercept user’s sessions on the router. Here, the attacker first configures his laptop as a WiFi hotspot, choosing a name commonly used in a public area, such as an airport or coffee shop. Once a user connects to that malicious router to reach websites such as online banking sites or commerce sites, the attacker then logs a user’s credentials for later use.

Man-in-the-middle attack prevention & tools

Most of the effective defenses against MITM can be found only on router or server-side. You won’t be having any dedicated control over the security of your transaction. Instead, you can use strong encryption between the client and the server. In this case, server authenticates client’s request by presenting a digital certificate, and then the only connection could be established.

Another method to prevent such MITM attacks is, to never connect to open WiFi routers directly. If you wish to so, you can use a browser plug-in such as HTTPS Everywhere or ForceTLS. These plug-ins will help you establishing a secure connection whenever the option is available.

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Tanmay is a passionate technology writer and a blogger who loves to write about security tips, web apps, social media and the latest updates happenings around the world of internet and technology. He is also a Microsoft Student Partner. Catch him on Twitter @techtsp.


  1. weird marketing tricks

    I am not a technical person but I use technology like facebook and other internet stuffs. Couple of days ago someone hacked into my facebook account and posted something terrible. Since then I am aware of hacking and I am trying to learn some technical stuffs to protect my personal data. This article is something great to read.

  2. One has to be very
    careful on Facebook having been hacked a few times myself going to your
    settings normally fixes it, however I use my cell number as a login to get back
    on. You cannot just use these social sites and expect to get away scot-free,
    make it private I do as do most of my family we all learnt the hard way. You always
    get one that spills the beans about you publicly though sadly, It happens on Gmail
    as well so get a record of your contacts on Gmail as mine was all altered when I
    got back on

  3. Actually, your prevention tips do NOT prevent a Man-in-the-Middle attack. Plugins like HTTPS-Everywhere and ForceTLS only force the use of an HTTPS/SSL/TLS connection. All HTTPS/SSL/TLS connections use a certificate issued by a third-party “certificate authority”. A Man-in-the-Middle attacker could still set up a WiFi hotspot that other computers might unknowingly connect to instead of the legitimate hotspot. The attacker would also establish their own separate HTTPS/SSL/TLS connection to the Internet through the legitimate hotspot. The attacker’s computer is the user’s HTTPS/SSL/TLS endpoint, and all Internet traffic (including certificates) is proxied to and from the user through the attacker’s computer. But meanwhile, on its way through the attacker’s computer, all traffic (including passwords, account numbers, social security numbers, etc.) passes unencrypted, as clear text, where it can be viewed, recorded, and even altered along the way.
    The only completely reliable defense against MITM attacks (unless you’re a sophisticated user who has other means) is to use some kind of locally installed client software that securely “tunnels” all traffic to a previously known and trusted server, which in turn proxies all the user’s traffic out to the Internet and back. Examples are corporate VPNs, anonymous Web browsing proxy services (if they use local client software), and SSH (secure shell) tunnels that only connect to already known, trusted servers.
    Public WiFi can be safe. Now you know how. Happy surfing.

  4. Conrad Klug

    I have a hacker using local MITM attacks in a number of different ways. I’m still kinda letting him lurk around tho. 😉

  5. jiji

    can someone use man in the middle on windows 10?

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