Yahoo Users Targeted as ‘New Part 55’ Leak Exposes 1.9 Million Logins

In April 2023, HEROIC analysts identified a combolist titled "YAHOO NEW PART 55" that a Telegram user uploaded, exposing 1,896,869 records. Tied to a leak date of April 24, 2023, the file pairs Yahoo-associated email addresses with plaintext passwords and the URLs they unlock. Why This Is Dangerous: This file specifically targets Yahoo account holders, giving attackers a focused list to run against Yahoo Mail and any other service where a Yahoo address is used to sign in. Because the passwords are plaintext, no extra effort is needed to read or use them. What Was Exposed: - Yahoo-linked email addresses - Plaintext passwords tied to those accounts - URLs showing where each credential pair was used Why This Matters: Yahoo Mail accounts often serve as recovery emails for banking, shopping, and social media logins, making them a valuable target. If attackers gain access to a Yahoo inbox, they can reset passwords on connected accounts, intercept codes sent by email, or use the account to send phishing messages to your contacts. If you reuse your Yahoo password elsewhere, credential stuffing can quickly turn one leaked login into several compromised accounts. How a Combolist Like This Works: A combolist compiles stolen email-and-password pairs, often organized by email provider, here specifically Yahoo, so criminals can run focused attacks against one platform at a time. These files spread through Telegram channels and dark web forums, where bots automatically test each pair against login pages in bulk. Check If You Are Affected: With almost 1.9 million records in this leak, the odds that a Yahoo user's information is included are real. HEROIC's free breach scanner checks your email against more than 400 billion leaked records, so you can find out immediately and secure your account before someone else logs in.