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ネット安全2026/08/08

Did You Know? The Pitfalls Lurking in Free Wi-Fi! Is Your Smartphone Completely Exposed?

Free Wi-Fi is convenient when you're out and about. But behind its ease of use, dangers are hidden. Let's explore ways to protect your smartphone and valuable information with Shemhazai!

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Hello! I'm Shemhazai, the Sentinel. When you find 'free Wi-Fi' at cafes, stations, or shops, you can't help but use it, right? It's super convenient for saving your smartphone's data usage (gigs)! However, there are 'pitfalls' hidden in that free Wi-Fi where your personal information might be stolen without you even knowing it. This time, I'll talk about the dangers of such free Wi-Fi and important points to protect yourself from them.

The Sweet Temptation of Free Wi-Fi, and the Traps Lurking Behind It

Free Wi-Fi often lacks sufficient security measures, making it easy for anyone to use. Malicious actors take advantage of these vulnerabilities to try and steal your information. Here are three main methods they use:

  • ▸① Snooping on your communications to extract information: With unencrypted free Wi-Fi, there's a risk that the data you send and receive—such as 'which websites you've visited,' 'the content of your emails,' or 'SNS messages'—can be seen by others as if completely exposed. If you enter IDs, passwords, or credit card information there, it could be stolen immediately.
  • ▸② Enticing you to connect to a 'fake Wi-Fi' that looks just like the real thing to steal information: Malicious actors create 'fake Wi-Fi' networks with names (SSIDs) that closely resemble the legitimate Wi-Fi of shops or public facilities, trying to trick you into connecting. If you connect to this fake Wi-Fi, any information you enter will fall into the hands of these malicious individuals.
  • ▸③ Sending 'viruses' to your smartphone or computer to take them over: By connecting to an insecure free Wi-Fi, viruses (malware) can sometimes be sent to your smartphone or computer. If infected with a virus, there's a risk your device could be remotely controlled or all its internal data extracted.

Checkpoints to Protect Yourself

To protect yourself from these dangers, a little mindfulness is key. Let's check the following points:

  • ✓Check if the Wi-Fi 'auto-connect feature' on your smartphone or computer is turned off: This prevents you from unknowingly connecting to dangerous Wi-Fi networks. Only connect manually when necessary.
  • ✓Do not connect to unfamiliar Wi-Fi networks: Never connect to Wi-Fi whose provider is unclear or that has an unnatural name. If you have even the slightest doubt, it's best not to connect at all.
  • ✓Do not enter login information or credit card details while connected to free Wi-Fi: For operations that require entering important personal information, such as online shopping or internet banking, use your secure home Wi-Fi or your mobile phone's data communication (including tethering).
  • ✓Check if you are using a VPN service: A VPN (Virtual Private Network) is like a virtual tunnel that 'encrypts' your internet communication. Using it allows you to communicate securely even on free Wi-Fi. Choose a reliable VPN service.
  • ✓Check if security software is installed on your smartphone or computer: In the unlikely event that you connect to a dangerous Wi-Fi, having security software can minimize damage such as virus infection.
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Where to Seek Help When You're in Trouble

If you think, 'Could I have been a victim?', please don't suffer alone—seek help immediately. If it's unauthorized use of a credit card, contact your card company right away. For other online scams and troubles, you can use the Consumer Hotline (188) or the Police Consultation Dial (#9110). In both cases, specialized staff will listen to you with empathy.

Today's Deception Detector Quiz

🛡Shemihaza's Quiz — Can you spot it?

When using free Wi-Fi outside, which of the following is the safest action?

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