Your Passwords May Be Exposed: The RU 20.09 Leak Hit 105,000+ Accounts

In March 2023, HEROIC analysts identified a large stealer log known as "RU 20.09" circulating on a Telegram channel. The file contained 105,391 records harvested from infected devices, including email addresses, plaintext passwords, and the URLs of the sites each login belonged to. Unlike a single-company data breach, this archive represents thousands of individual computers that were compromised by information-stealing malware and had their saved credentials collected in bulk.

Why This Is Dangerous

What makes a log of this size so dangerous is the sheer volume of ready-to-use logins it hands to attackers. Each record pairs an email address with its plaintext password and the exact website that password unlocks, meaning no guessing or cracking is needed. With over 105,000 records in one file, an attacker can automate login attempts across banking sites, email providers, and social media platforms at scale, testing thousands of accounts in minutes.

What Was Exposed

This leak included the following data types:

• Email addresses
• Plaintext passwords
• URLs linked to each set of credentials

Why This Matters

A leak this large is a prime source for credential stuffing, where attackers feed stolen email and password pairs into automated tools that try them across hundreds of other websites. Because so many people reuse the same password on multiple accounts, one infected device can open the door to account takeover on services the victim never even associated with the original leak. At this scale, the data is also valuable enough to be resold repeatedly, extending the risk long after the initial theft.

How Stealer Logs Work

A stealer log is generated by information-stealing malware, malicious code that infects a device through sources like pirated software, fake installers, or malicious attachments. Once running, it quietly extracts saved browser passwords, autofill entries, and active login sessions, then packages everything into a text file for the attacker. Large logs like this 105,391-record file are often compiled from many infected machines and traded or given away on Telegram channels, which have become a major distribution point for stolen credentials.

Check If You Are Affected

With over 105,000 records in this single stealer log, the odds that your email address is included are real. HEROIC's free breach scanner checks your email against a database of more than 400 billion leaked records, including stealer logs like this one, so you can quickly find out if you have been exposed and change any reused passwords before someone else uses them first.