One Telegram Upload. The Herin Yahoo Dump Had 498,630 Records.

HEROIC Analysts Uncover the Herin Yahoo Dump UHQ 2

HEROIC's threat intelligence team identified a massive stealer log titled "Herin yahoo dump UHQ 2" uploaded to Telegram by an anonymous user, dated January 18, 2023. The file contained 498,630 records, each pairing a Yahoo-linked email address with a plaintext password and the URL of the login page the credentials were used on.

One Telegram Upload. The Herin Yahoo Dump Had 498,630 Records.

A single file, uploaded in a single moment by a single anonymous account, put nearly half a million working Yahoo logins into circulation. That is the scale problem with stealer logs like this one: they are compiled quietly over time from many infected devices, then released all at once, turning one Telegram post into a mass event affecting hundreds of thousands of people who never saw it coming.

What Was Exposed in the Herin Yahoo Dump UHQ 2

• Yahoo and related email addresses used as account logins
• Plaintext passwords tied to those accounts
• The website URLs each credential pair was used on

Why This Matters for the 498,630 People in This Dump

At this scale, criminals do not review records one by one, they run them through automated credential stuffing tools that test every email and password pair against dozens of popular sites in seconds. Anyone among the 498,630 affected who reused their Yahoo password elsewhere faces a real risk of account takeover on email, banking, or shopping accounts.

How a Dump This Large Gets Assembled

This data is the output of infostealer malware, which infects devices through phishing emails, cracked software, or malicious downloads, then silently harvests saved browser passwords. A dump of nearly half a million records is typically built by combining the output of many infections over months before being packaged, labeled, and shared or sold on Telegram.

Check If You Are Affected

With almost 500,000 records in a single upload, the chance that your email is somewhere in this dump, or another one like it, is real. HEROIC's free breach scanner checks your email against a database of more than 400 billion compromised records, so you can quickly find out and secure any accounts still using an exposed password.