Protecting our data online is never going to be an easy task, especially nowadays when attackers are regularly inventing new techniques and exploits to steal your data. Sometimes their attacks will not be so harmful to 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.
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) inhibits the conversation to eavesdrop and carries on a false conversation with Rob, on behalf of Mike. First, Mike asks Rob for his public key. If Rob provides his key to Mike, Alex intercepts, and this is how the “man-in-the-middle attack” begins. Alex then sends a forged message to Mike that claims to be from Rob but includes 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, the attacker mostly uses a WiFi router to intercept the user’s communication. This technique can be worked out by exploiting a router with some malicious programs to intercept users’ 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.
Read: What is Replay Attack and how do you prevent it?
Man-in-the-middle attack prevention & tools
Most of the effective defenses against MITM can be found only on the 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, the server authenticates the 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 do so, you can use a browser plug-in such as HTTPS Everywhere or ForceTLS. These plug-ins will help you in establishing a secure connection whenever the option is available.
Read next: What are Man-in-the-Browser attacks?