SPIDER1CODE

How Spider Got Hacked Through Google Calendar

Dear readers, welcome to a brand new article ✨

"How Spider Was Hacked via Google (Google Calendar)"

On May 29, 2025, a strange and unique security vulnerability was disclosed, linked to a Chinese state-sponsored group known as APT41, short for Advanced Persistent Threat 41.

> Hold on, is this the same “apt” from apt update and apt upgrade?

No, dear reader, this is not the APT you're thinking of.

This APT refers to a category of advanced cyber threats, often supported by nation-states — in this case, China.
Yes, dear reader, the land of Bruce Lee!

APT41 has been involved in global cyber espionage and large-scale data theft campaigns. It's also known under various aliases such as:

Wicked Panda

Brass Typhoon

Winnti, among others...

Their targets are usually sensitive sectors like:

Governments

Shipping & Logistics

Media & Entertainment

Technology

Automotive Industry

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🧨 Back to the Story: The Attack Itself

The attack revolved around the use of Google Calendar as a Command-and-Control (C2) channel.

> Wait... did they really control victims just by using Google Calendar?

Yes, dear reader, you read that right!
You're not reading from a fake blog — this is real cyberwarfare!

In this attack, APT41 used a newly developed malware called TOUGHPROGRESS that relies on Google Calendar to remotely execute commands on infected devices and receive the results.

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🪝 How the Attack Was Carried Out:

Victims received a phishing email containing a link to a compromised government website.

That link downloaded a ZIP file containing:

A folder with image files named 1.jpg to 7.jpg (they appeared to be insect images)

A shortcut file (LNK) disguised as a PDF document

Once the victim opened the LNK file:

A fake PDF popped up, claiming the listed species need to be declared for export

But behind the scenes, malware execution began

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🧬 The Malware Workflow Includes 3 Stages:

1. PLUSDROP

A DLL that decrypts and loads the next payload directly in memory.

2. PLUSINJECT

Uses process hollowing to inject the next-stage malware into a legitimate system process (svchost.exe).

3. TOUGHPROGRESS

The final payload that communicates with Google Calendar for remote command execution.

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📆 How TOUGHPROGRESS Uses Google Calendar for C2:

It connects to an attacker-controlled Google Calendar account

It creates a calendar event on a hardcoded date (May 30, 2025)

It stores stolen data inside the event description

Attackers add encrypted commands in other calendar events (July 30 & 31, 2025)

The malware:

Fetches and decrypts these commands

Executes them on the victim’s machine

Uploads the results by writing them back into new calendar events

This technique allows attackers to control infected machines stealthily, using a trusted service that doesn’t usually raise any red flags.

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⚠️ Why This Method is Smart and Dangerous:

Communication with the malware looks legitimate, since it's through Google services

No need for dedicated C2 servers (harder to block or trace)

Can bypass firewalls easily, because Google Calendar is usually allowed in organizations

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🛡️ Google’s Response:

The malicious calendar activity was discovered in October 2024

Google shut down the compromised calendar and terminated related Workspace projects

Affected organizations were notified, but the full scope of the campaign remains unknown

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✅ Final Thoughts:

This attack showcases how cybercriminals are evolving and now using trusted cloud services like Google Calendar and Google Drive to:

Avoid detection

Blend in with normal traffic

Make tracking and mitigation much harder

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Thank you for reading! 🤍✨
Stay informed, stay safe.

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