The ‘CZ’ Stealer Log Quietly Exposed 164,512 Plaintext Passwords

In January 2023, a stealer log identified only as "CZ" was uploaded to Telegram by an anonymous user. It contained 164,512 records of email addresses, plaintext passwords, and the URLs tied to each login, quietly collected from devices infected with information-stealing malware long before anyone noticed it had circulated.

Why the CZ Stealer Log Went Unnoticed for So Long

Stealer logs like this one rarely make headlines. There's no press release, no official notification, just a file passed quietly between Telegram channels and cybercrime forums. That silence is exactly what makes this kind of leak dangerous: passwords stolen in 2023 may still be sitting unchanged on real accounts today, giving attackers a long, quiet window to exploit them.

What Was Exposed

• Email addresses
• Plaintext passwords
• URLs identifying which site each password unlocks

Why This Matters

With passwords stored in plaintext and matched to their exact login pages, this data is immediately usable for credential stuffing, where automated tools try stolen logins across banking, email, and shopping sites. Anyone whose credentials appear in the CZ log faces a real risk of account takeover, identity theft, and downstream financial fraud, especially if the password has never been changed.

How This Kind of Stealer Log Gets Built

Malware installed on a victim's device, often bundled with pirated software or hidden in a malicious download, quietly copies saved browser passwords and the web addresses they belong to. That stolen data is sent back to whoever controls the malware, who compiles logs like this one from many infected computers and passes them along on Telegram or dark web marketplaces, often for free or for a small fee.

Check If You Are Affected

You won't get a notification if your information ends up in a log like this one, which is why checking for yourself matters. HEROIC's free breach scanner searches a database of more than 400 billion leaked records to tell you whether your email or password has surfaced in this or any other leak, so you can change it before someone else uses it first.