My Inventory disappeared

[KsbV]

I am rarely on steam anymore as I don't play games much. I logged on today for some fun and realised all my items (mostly CS2) are gone. I checked the trade history and found that all of my items were traded to some random person 2 days ago. How did this happen? I did not touch my steam account for months, there was nothing on my steam guard or 2 factor authentication. I did not give me account details to anyone, so what should I do? Thanks.

[Maria]

Originally posted by KsbV:

... I did not give me account details to anyone, so what should I do? Thanks.

You certainly did, unknowingly. Phishing or malware, usually.

Do all these steps to secure your account:

1. Scan for malware.
https://www.malwarebytes.com/

2. Check that the email and phone number on the Steam account are still yours.

3. Deauthorize all other devices.
https://store.steampowered.com/twofactor/manage

4. Change passwords from a clean computer.

5. Generate new backup codes for your Mobile App. https://store.steampowered.com/twofactor/manage

6. Revoke the API key (there should be no key).
https://steamcommunity.com/dev/apikey

No refund/reverse trade:
https://help.steampowered.com/en/faqs/view/3B6E-B322-2400-8D24