Security on Lin's Blog

iOS Packet Sniffer on macOS

Thu, 02 Feb 2017 18:37:10 +0000

When developing iOS apps, or when doing things you’d rather keep under wraps, you may need to capture packets. For capturing packets on a computer, Wireshark is the top choice. But what if you want to capture packets on your iOS device (iPhone, iPad)? You could set up a proxy and have the iOS device connect through it, or jailbreak and run tcpdump on the device. But both approaches are too troublesome. Here I recommend the rvictl command included in the Xcode Command Line Tools. It requires no complicated setup or jailbreak, and with just one command you can capture packets on your computer using any software.

AES Encrypt/Decrypt File on Mac OS

Wed, 28 Dec 2016 14:06:30 +0000

When you need to send sensitive data through Facebook or email, such as a Google API token or a company’s annual accounts, do you really trust those online services? Personally, I don’t. There are too many possibilities, from hacker attacks to poor internal controls at a company that let employees view customer data. Because of these possibilities, I’m not really willing to send confidential data over the internet. But in this day and age, sending data without using services like email or Facebook Messenger is almost impossible. In that case, you can use AES to encrypt the file, and then share the password through a channel you trust, such as a phone call or in person. Or at the very least, send the password through a different channel than the file, to reduce the risk of everything being compromised at once.

Setting Up Account Security to Make Your Facebook Account Safer

Sat, 03 Dec 2011 17:01:56 +0000

Are you sure there are no Trojans or viruses on your computer? Can you say your computer is completely safe? Are you worried that your Facebook account might be hijacked? Here I’m going to show you how to turn on Facebook’s free service, Account Security. It gives your account more protection, such as encrypted connections, login notifications, and login approvals.

Turn On Google 2-Step Verification and Add Another Lock to Your Google Account with Your Phone!

Tue, 09 Aug 2011 13:09:12 +0000

Some people who play online games may have heard of the “communication lock.” It’s an anti-theft measure that game companies came up with. Before you can log in to your game account, you have to call a dedicated line from the phone number you registered with the game company, and only after the call connects can you log in. This method prevents a lot of gamers from having their accounts stolen. After all, hackers can easily get your username and password, but they surely can’t take your phone too, right? The Google 2-Step Verification I’m introducing today is actually a lot like that communication lock.

Avast – A Top Free Antivirus with Sandboxing, Site Blocking, Scheduled Scans, Startup Scans, and More!

Sun, 19 Jun 2011 11:52:38 +0000

When you buy a new computer, I think the most troublesome part is choosing antivirus software. For ordinary people, a computer without antivirus is genuinely dangerous. But many antivirus programs cost money, pirated copies are unsafe, and free ones might not be strong enough and leave room for viruses and trojans. Here I want to introduce a “free” antivirus called Avast. It’s one of the best free antivirus programs out there, and in my opinion, it’s number one! It even beats some paid antivirus programs. So if you want to save the money you’d spend on antivirus software, give Avast a try.

Microsoft Security Essentials - Microsoft's "Free" Antivirus!

Sat, 30 Apr 2011 19:29:33 +0000

Microsoft Security Essentials is a “free” antivirus program offered by Microsoft. Its biggest feature is that it’s free! It’s also from the company that people affectionately call M$. Microsoft Security Essentials performs reasonably well, and its virus protection is decent. If you’ve just set up a new computer and you’re a fan of Microsoft products, I suggest you take a look at this antivirus.

What Is a Malicious Link? How Do You Protect Against Malicious Link Attacks?

Wed, 27 Apr 2011 17:47:13 +0000

A “malicious link” is an attack method that is especially well suited to social networking sites. It’s relatively easy to pull off, and its success rate is quite high. For example, the recent Facebook scam “How to see who viewed your profile!!” is a malicious link attack. A malicious link can be explained in one simple sentence: it’s a URL that contains a Trojan, a virus, or something that can take control of your computer. When you click on such a link, your computer has probably already been infected.

Think Your Privacy Settings Keep You Safe? The Hidden Risks of Facebook Games and Personality Quizzes

Mon, 21 Mar 2011 01:51:42 +0000

Does setting up your privacy settings really keep your personal data from leaking? ↑↑

Not long ago, many bloggers and news outlets wrote at length about the privacy risks of Facebook itself. So many users went and set up their "privacy settings," thinking that as long as they did, nothing would go wrong. In reality, though, the huge number of games and personality quizzes on Facebook can also cause your personal data to leak. Many users don't know this, so let's analyze it below.

Do You Still Have Privacy? Musings on the Dangers of Making Personal Information Public

Mon, 21 Mar 2011 01:15:36 +0000

Many people today advocate for privacy, saying you should share as little personal information online as possible, or none at all, because posting it online carries many dangers, the most common being harassment. But I think many people simply don’t pay attention to privacy (at least, that’s what I’ve observed). Plenty of people generously make their phone numbers, addresses, and other details public, and some even dare to upload intimate photos online. Others are more aware and understand the dangers of making personal information public, so they don’t openly post their data online. Instead, they set up some protections, such as passwords and Facebook privacy settings. Honestly, these measures barely work. The most fundamental and safest approach is simply not to put anything online at all.

Mail Bomb - A Purely Mischievous Email Bomb~

Tue, 05 Oct 2010 22:28:00 +0000

What is a mail bomb? You've probably never heard this term before... In the past, people were more likely to hear about "instant messenger bombs." These are programs that keep sending messages to an instant messenger contact, until the other person gets disconnected from receiving too many messages in a short time. A Mail Bomb is similar. Translated directly into Chinese, Mail Bomb is called "mailbox bomb." Like instant messenger bombs, it sends lots of messages to someone else. But the difference is that a Mail Bomb is really just a prank... it has no real function, and it can't actually fill up someone's mailbox, because with today's mailbox sizes, that's very hard to do. And don't even think about using my Mail Bomb system to send spam, because this program sends many emails to a single mailbox, not one email to many mailboxes. Now let me show you how to use Mail Bomb~

Encrypt Your Instant Messages with MSNShell and SimpLite-Yahoo to Prevent Admin Snooping

Fri, 22 Jan 2010 19:26:07 +0000

Yesterday, while reading the newspaper, I came across an article saying that a supervisor at 104 Job Bank had been monitoring employees’ instant messages. I won’t comment on that, since it’s an adult matter. From the company’s point of view, of course they want to take measures to prevent employees from leaking information, and the company had told employees that instant messaging software would be monitored. But from the employee’s point of view, it must be really annoying, since nobody likes being watched. Oops, I’ve drifted off topic a bit~~ Anyway, this post is going to teach you to use two programs: MSNShell and SimpLite-Yahoo.

Online Proxy IP (Proxy): Get Around Network Admin Controls

Sat, 10 Oct 2009 19:20:00 +0000

Have you ever wanted to visit a website, only to find it blocked? (Usually it’s adult videos…) Or maybe you mistyped something while logging in and got your IP blocked? When that happens, you can use the “proxy IP” (Proxy) introduced in this post. A proxy IP (Proxy) is really a web proxy, and it can hide your identity while you browse. It sounds like magic, but the principle is not hard to understand. You first connect to the proxy IP (Proxy) server, and then connect to the website from there. In other words, you go online through a proxy server, so the IP address left behind is not your own. But please don’t use this for bad things, because most proxy companies keep user data. If you do something illegal, it can still be traced XD

A Brief Look at the Principle Behind Packed Programs

Tue, 07 Jul 2009 20:29:10 +0000

Most people have heard of packers, such as UPX, but do you know how they work? Have you ever tried writing one? Is it hard? Actually, the principle is quite simple. Let me, Feng-lai, explain it for you~

The first step in writing a packer is to get the binary file of the program you want to pack. Everyone knows that every file on a computer is a binary file, right? A binary file is made up entirely of 0s and 1s. So what do you do with it once you have it? Encrypt it, of course. The simplest encryption method would be to invert every bit: each 0 becomes a 1 and each 1 becomes a 0. But you can’t just run the encrypted file directly, so the second part comes next.

HxD - An Excellent Hex Viewer

Sun, 28 Jun 2009 09:00:10 +0000

Today I am introducing a program called HxD. It lets you view a file’s hexadecimal bytes. Although HxD is free, it is no less capable than professional-grade editors. HxD not only supports basic hex viewing but can also directly control memory. HxD also has an export feature: you can export modified files directly as source files for languages such as VB or C++. Personally, I think anyone who often works with computers should keep it on a USB drive, just in case.

FixDwndp: Fixing the Problem of Not Being Able to Reach Microsoft Websites

Sat, 20 Jun 2009 20:26:08 +0000

While browsing the web today, I was surprised to find that I couldn’t connect to Microsoft’s website. It reminded me of the disaster when my computer broke down last time…. and sure enough, it really happened again!

Last time, for some unknown reason, my computer couldn’t connect to any Microsoft-related sites, nor could it open antivirus software websites, and the virus definitions wouldn’t update either. Back then I just reinstalled everything directly, since the computer had been used for quite a while. But this time the computer was barely bought and it’s already acting up @@

After all that rambling, the reason I’m recommending FixDwndp today is this: I personally suggest that readers of this article go check right away whether your computer has the following symptoms:

You can't get into the Microsoft official website

You can't get into the websites of major antivirus software

Automatic update notifications haven't popped up for a long time

Antivirus software can't update its virus definitions

Watch Out! Gmail Inbox Received Emails Signed "Me"?

Sat, 20 Jun 2009 12:17:23 +0000

Gmail users have probably been getting a lot of emails signed “Me” lately, right?

But I never sent an email to myself, so why am I receiving them?

Here is a reminder: if you receive this kind of email, I suggest you delete it right away.

These emails usually don’t contain any ads.

They just have one sentence asking you to click a link.

I don’t know what happens after you click it!!

Fixing Errors Caused by a Virus

Sun, 03 May 2009 10:00:00 +0000

Some viruses use the registry to damage computers. Basically, I’m only posting one example here; the registry has many other places where things can be hidden,
so if you don’t know much about computers, don’t try to change other places. At best nothing happens, at worst the computer is ruined. Following the steps below is safe.
“Start” “Run”, type “regedit”
HKEY_CLASSES_ROOT\exefile\shell\open\command

HKEY_CLASSES_ROOT –> exefile –> shell –> open –> command

Then check the “(Default)” value. If it is “%1” %* it is normal. If it isn’t, your computer has been infected.
Double-click it and change it to “%1” %*

Also, pay attention to other places!!