Public WiFi=Naked Running? An article that explains its risks and protections

Have you ever had the experience of running out of mobile data while shopping, and eagerly connecting to "Free WiFi" when you see it; Habitually searching for wireless networks around coffee shops and others; The first thing to do when staying at a hotel on a business trip is to ask for the WiFi password at the front desk. Most people think that it's just going online, what risks can there be. But the reality is that every password, transfer, and chat record you enter on public WiFi may be clearly visible to a stranger next to you.

This is not an exaggeration. This article does not discuss mysterious hacking techniques, but only talks about three things: where is the danger of public WiFi, how attacks occur, and how ordinary people can protect themselves.

Many people think of hackers like those in movies who invade bank systems with just a few keystrokes when it comes to cybersecurity. But the risks of public WiFi are actually simpler and more common than you imagine. The core concept is called 'man in the middle attack'. Under normal circumstances, when you connect to WiFi internet, data will flow from your phone to the router and then to the website server. But in an insecure public WiFi environment, attackers can plug in and allow data to flow from your phone to the attacker, then to the router, and finally to the website server. You think you are directly communicating with the website, but in fact, all the data has passed through the attacker's device first. He can see, change, or steal.

Remember, the danger of public WiFi lies not in how skilled hackers are, but in the fact that the network itself is a public channel where anyone can listen. This is like making a phone call in an open office, where people around you can hear every word you say as long as they want to listen. The only difference is that you are completely unaware of eavesdropping on the internet.

Knowing the concept of a middleman and looking at how it operates, the entire process actually only involves three steps, and the technical threshold is much lower than you imagine. Attackers usually set up a fake WiFi first. He can create a WiFi hotspot with the same name as a shopping mall or coffee shop using a regular laptop or even a mobile phone. For example, if a shopping mall is called "Starbucks\_WiFi", it can create a "Starbucks\_WiFi Free" or simply create a hotspot with the same name. Your phone will automatically select the connection with a stronger signal, and the attacker's device is often closer to you and has a stronger signal. So you unknowingly connected to the attacker's device. This step is called "Evil Gemini Attack", which means a fake twin who looks exactly the same.

After connecting to fake WiFi, all your network requests will pass through the attacker's device. If the website you visit is not encrypted, that is, the URL is http:// instead of https://, then the account password, search content, and browsing history you enter are all transmitted in plaintext, which attackers can directly read. Even if the website is encrypted, attackers can use SSL stripping technology to downgrade your encrypted connection to an unencrypted one and continue eavesdropping.

After obtaining the data, attackers can do things such as stealing your social media account, email, and online banking password, tampering with the web pages you visit, such as changing the receiving account on the payment page to their own, implanting Trojans or viruses in the files you download, recording your browsing habits, and using them for precise fraud. Throughout the process, you may just feel that the internet is a bit slow today and have no idea that your information has been stolen.

Not all public WiFi is equally dangerous. Open WiFi without password, anyone can connect, including attackers, without any authentication. Try not to connect or only browse without logging in. The "twin" WiFi with similar names may be a fake hotspot set up by attackers to induce connections. When encountering it, you should confirm the correct WiFi name with the staff. In crowded and noisy public places such as airports, train stations, and shopping malls, attackers are mixed in the crowd and difficult to detect, with more targets, requiring special vigilance. The WiFi that pops up on the login page after connection may be a "phishing portal" used to deceive your phone number or social media account. Do not enter personal information on the login page casually. A simple way to determine this is that if a public WiFi does not require a password, has a casual name, and immediately pops up a page asking for a phone number after connection, then it is likely to be insecure.

There are several widely circulated claims about public WiFi, but they are only half true. Some people think that I am connected to a legitimate merchant's WiFi and should be fine. The WiFi of legitimate merchants is indeed safer than anonymous hotspots, but this does not mean it is absolutely secure. On the one hand, the merchant's router may have known vulnerabilities; On the other hand, attackers can set up hotspots with the same name in the same space, and you can't even distinguish which one is real. A more accurate understanding is that legitimate merchants' WiFi reduces risks, but does not eliminate them.

Some people also think that I am using an HTTPS website and not afraid of being eavesdropped. HTTPS can indeed encrypt data, but it is not omnipotent. Attackers can downgrade your connection through SSL stripping technology, or manipulate the page where you enter your password. Moreover, not all pages of many apps and websites are fully encrypted. A more accurate understanding is that HTTPS significantly increases the threshold for attacks, but caution is still needed in public WiFi.

Some people think that if I don't log in to online banking and just browse videos, it's okay. Even without logging into online banking, your WeChat chat history, browsing history, location information, and search keywords are all valuable data. Attackers can use this information to understand your lifestyle habits and social relationships, and then carry out precise fraud. A more accurate understanding is that there is no insignificant data, and every piece of your information may be exploited.

Is it safe to install antivirus software. Antivirus software mainly protects against viruses and malicious software, and is often powerless against network layer eavesdropping such as man in the middle attacks. It can detect viruses on your device, but cannot detect who is intercepting the data being transmitted in the network. A more accurate understanding is that antivirus software is necessary, but it cannot replace safe internet habits.

Talking about so many risks is not to make you afraid to connect to public WiFi from now on, but to help you establish a set of judgment criteria. If the mobile data is sufficient, prioritize using your own data. Most of the current data plans are very cheap, and using data to access the internet is much safer than public WiFi, which is the simplest and most effective protection. If it is necessary to connect to public WiFi, first confirm the correct WiFi name and password with the on-site staff. Do not search for the connection yourself, and be particularly alert to hotspots with similar names that do not require a password.

After connecting, try to avoid logging into the payment APP, do not enter sensitive information such as ID number, bank card number and password, do not download and install files from unknown sources, do not visit websites without HTTPS encryption, and it is relatively safe to have a small lock icon in front of the website. Things that can be done include reading news, checking maps, and browsing web pages that do not involve logging in. If you often need to handle work emails or sensitive information on public WiFi, it is recommended to use a trusted VPN service. VPN will establish an encrypted channel between your device and server, so even if data is intercepted, attackers cannot read the content. Remember this metaphor, public WiFi is a public corridor where anyone can peek; A VPN is like building an encrypted private pipeline for you in the hallway, where outsiders cannot see what is being transmitted inside.

After leaving public places, remember to turn off the WiFi automatic connection function to avoid your phone automatically connecting to unsafe hotspots without your knowledge. At the same time, regularly check the WiFi list saved in your phone and delete any hotspots that are no longer in use.

Network security is often not a technical issue, but a matter of awareness. You don't need to become a security expert, nor do you need to memorize complex technical terms. You just need to remember one thing, in a public network environment, assuming that your data may be seen by others, and then adjust your behavior accordingly. If possible, do not use public WiFi. Do not perform sensitive operations when necessary, and use your own data or VPN for important operations. These three measures can help you avoid over 90% of public WiFi security risks. Security is not a tool, but a habit. From today on, the next time you see 'Free WiFi', think three seconds more.