Intro: The Plot Twist No One Saw Coming
Picture this: You install a Chrome extension for a "14-day free trial." But what if I told you… I turned those 14 days into 7,978 years? 😱
Spoiler: It’s easier than you think. Let’s spill the tea ☕ on how developers set up trials, how I “hacked” one, and how to stop folks like me!
NOTE: You can download the extension source code using this extension:
Part 1: How Free Trials Usually Work (aka “The Boring Stuff”)
Most developers track trials like this:
// When you install the extension...
chrome.runtime.onInstalled.addListener(() => {
chrome.storage.local.set({ installDate: Date.now() }); // 🗓️
});
// Later, they check if you’re broke & need to pay 💸
chrome.storage.local.get(["installDate"], (result) => {
const trialEnd = result.installDate + (14 * 86400000); // 14 days in ms
if (Date.now() > trialEnd) {
alert("Trial over! Give us money NOW."); // 😤
}
});
Translation: They save the day you installed it and nag you after 14 days. Classic.
Part 2: How I Became a Trial Wizard 🧙♂️ (Thanks, DeepSeek!)
So, I peeked into the extension’s code (don’t try this at home, kids 🚫). But let’s be honest, I’m too lazy to manually sift through messy JavaScript files. 😴 Instead, I used DeepSeek, an AI model designed for digging through code and finding loopholes like a pro. 💀
Step 1: Pass the Code to DeepSeek
I uploaded the JavaScript file (the bundled code) and simply prompted DeepSeek with something like:
“Analyze this code for vulnerabilities or ways to bypass trial expiration logic.”
DeepSeek quickly spotted the key section of code responsible for managing the trial period:
chrome.storage.local.set({ installDate: Date.now() });
Step 2: Time Travel, But for Code
DeepSeek also suggested a sneaky modification:
“You can replace
Date.now()
with a future timestamp to extend the trial indefinitely.”
So, I followed the advice and tweaked the code to:
chrome.storage.local.set({
installDate: new Date('9999-12-31').getTime() // ⏳
});
The Result?
The extension now thought I installed it on December 31, 9999🤣.
That means it calculated the trial expiration date as millions of days into the future, effectively giving me a never-ending trial. 🏝️
Thanks to DeepSeek, I didn’t even have to break a sweat combing through the code! 😅
Why This Works: The Secret Sauce 🍝
Let’s make this fun and interactive! Here's a simplified breakdown of why my little time-travel trick worked:
The Extension’s Original Brain 🧠
When you install the extension, it thinks:
“Okay, let’s save today’s date and track when 14 days are up.”
- Step 1: The Install Date 🗓️ The code saves the current date in milliseconds:
chrome.storage.local.set({ installDate: Date.now() });
Translation: “Hey, they installed this on January 28, 2025. Write that down!”
- Step 2: Trial Expiry Logic 💣 Every time you use the extension, it calculates if the trial is over:
chrome.storage.local.get(['installDate'], (result) => {
const trialEndDate = result.installDate + (14 * 24 * 60 * 60 * 1000); // 14 days in ms
if (Date.now() > trialEndDate) {
alert("Your trial has ended. Please upgrade.");
}
});
Translation: “Today is February 11, 2025. Hmm… did 14 days pass since January 28, 2025? Yup? Time to ask for $$$!”
My “Hack” Logic: Future Me Is Clever 🕶️
Instead of letting the extension record today’s date, I gave it a wild date way in the future:
chrome.storage.local.set({ installDate: new Date('9999-12-31').getTime() });
Here’s why this fooled it:
Step 1: New Install Date 🛸
By telling the extension that I installed it on December 31, 9999, it believed this fake date without question.Step 2: Expiry Logic Becomes a Joke 🤣
When it checked for the trial expiration, it did this:
const daysLeft = (installDate + trialPeriod - Date.now()) / 86400000;
Here’s how the math worked:
-
Install Date:
253,402,300,799,000 ms
(December 31, 9999). - Trial Period: Add 14 days → irrelevant because the install date is already ridiculous.
-
Today’s Date:
1,730,084,800,000 ms
(January 28, 2025).
The calculation:
const daysLeft = (253,402,300,799,000 - 1,730,084,800,000) / 86400000;
Result? 2,912,783 days left in the trial. That’s 7,978 years!
- The Extension’s Reaction 🤯 “Oh, cool! The trial’s still valid… and will be for the next few millennia!”
Well, you’ve done it 👏
Why This Is So Silly 😂
By giving the extension a fictitious install date in the future, I effectively bypassed its simple logic. It trusted the installDate
without questioning whether it made sense.
Lesson for Developers: Trust Issues Are Good 😅
If your extension relies on client-side storage to manage trials, it’s like leaving your door unlocked in a neighborhood full of curious hackers. 🏚️ Always validate your logic with server-side checks and encryption!
Stay tuned for ways to keep sneaky wizards like me at bay. 🧙♂️💀
Part 3: How to Stop Sneaky Hackers Like Me 🛑
Developers, don’t panic! Here’s how to protect your trial:
1. Server-Side Checks (aka “Stop Trusting Browsers!”) 🌐
Store install dates on YOUR server, not the user’s browser:
// On install, ping your server
fetch('https://your-api.com/trial', {
method: 'POST',
body: JSON.stringify({ userId: 'UNIQUE_ID', installDate: Date.now() })
});
Pro Tip: Add a setInterval
to check the server daily. No more funny business!
2. Encrypt the Install Date 🔐
Turn installDate
into gibberish with CryptoJS:
const encryptedDate = CryptoJS.AES.encrypt(
Date.now().toString(),
'SuperSecretKey123' // 🕵️♂️
);
chrome.storage.local.set({ installDate: encryptedDate.toString() });
Hackers: “Is this… Spanish??” 😵
3. Obfuscate Your Code (Make It Unreadable) 🤯
Use tools like JavaScript Obfuscator to turn:
chrome.storage.local.set({ installDate: Date.now() });
Into:
var _0x44020f=_0xe31d;function _0x5aa4(){var _0x113da9=['storage','local','26PGlJXt','12NVzeFQ','197296ESbWxY','137768wmlklv','3645515rhHAQx','7167171ZYajOo','7940184eINQOh','6AOUSNv','3huOqcq','189zrpgHD','126MZIqID','2459272XcgHUX','6WRHEFk','115780ldQySt'];_0x5aa4=function(){return _0x113da9;};return _0x5aa4();}function _0xe31d(_0x1826f8,_0x68a104){var _0x5aa47b=_0x5aa4();return _0xe31d=function(_0xe31d1,_0x3a8241){_0xe31d1=_0xe31d1-0x175;var _0x164585=_0x5aa47b[_0xe31d1];return _0x164585;},_0xe31d(_0x1826f8,_0x68a104);}(function(_0x3811c6,_0x2d46f9){var _0x361065=_0xe31d,_0x46812e=_0x3811c6();while(!![]){try{var _0x31a7c6=parseInt(_0x361065(0x176))/0x1*(parseInt(_0x361065(0x17c))/0x2)+parseInt(_0x361065(0x182))/0x3*(-parseInt(_0x361065(0x175))/0x4)+parseInt(_0x361065(0x17e))/0x5*(-parseInt(_0x361065(0x181))/0x6)+-parseInt(_0x361065(0x183))/0x7*(parseInt(_0x361065(0x17d))/0x8)+-parseInt(_0x361065(0x184))/0x9*(parseInt(_0x361065(0x177))/0xa)+parseInt(_0x361065(0x17f))/0xb*(parseInt(_0x361065(0x17b))/0xc)+parseInt(_0x361065(0x17a))/0xd*(parseInt(_0x361065(0x180))/0xe);if(_0x31a7c6===_0x2d46f9)break;else _0x46812e['push'](_0x46812e['shift']());}catch(_0x3f6589){_0x46812e['push'](_0x46812e['shift']());}}}(_0x5aa4,0x634fd),chrome[_0x44020f(0x178)][_0x44020f(0x179)]['set']({'installDate':Date['now']()}));
Hackers: “Is this code or hieroglyphics?!” 🐍
4. Fingerprint Their Device 🖨️
Use FingerprintJS to tie the trial to their device:
FingerprintJS.load().then(fp => fp.get()).then(result => {
const fingerprint = result.visitorId; // Unique to their browser
// Store fingerprint + installDate on your server
});
Result: If they reinstall, you’ll KNOW. 👀😂
Conclusion: Don’t Let Hackers Win!
Client-side trials are like leaving your car unlocked in a sketchy neighborhood 🚗💨. Use server checks, encryption, and fingerprints to keep your extension safe!
Ethical Note: This post is for laughs and learning—not a hacking manual! Always respect developers’ hard work. 🌟
Thanks for reading! Now go forth and build unhackable trials. 🛠️
Top comments (2)
Unless they validate your trial on their backend?
Validating subscriptions on the front end is like keeping admin credentials in plaintext in your HTML, nobody does that (if they do, it'll be a very quick lesson on basic security).
Exactly! Validating on the backend makes it much harder to bypass. Front-end validation alone is too easy to exploit and leaves everything exposed
I’ve explored many front-end-based extensions, and most have vulnerabilities. Recently, I found one popular extension with this exact loophole:
I wrote this article to share the fun and spread awareness. :)