One SMTP Password Could Unlock a Chain of Accounts

HEROIC's Dark Web surveillance flagged a stealer log collection titled "Good SMTPs Cyberdataofficial" that was circulated in August 2025. This dump contains 1,667 records of SMTP (Simple Mail Transfer Protocol) credentials — each including an email address, a plaintext password, and the associated URL. Unlike typical credential leaks, SMTP access gives attackers the ability not just to read email but to send messages as the victim, making a single compromised password the starting point for phishing campaigns, business email compromise, and cascading account takeovers.

Plaintext SMTP Credentials: A Double Threat

All 1,667 passwords are in plaintext and verified as working. SMTP credentials are particularly dangerous because they grant both inbox access and the ability to send authenticated emails. An attacker with working SMTP credentials can impersonate the account holder, send phishing emails to their contacts, request password resets on connected accounts, and use the compromised email server as a launch pad for further attacks — all without any technical barrier.

What Was Exposed

• Email Addresses — validated accounts with confirmed SMTP send capability
• Plaintext Passwords — verified working credentials that bypass all security prompts
• URLs — mail server endpoints and associated service URLs revealing infrastructure details

From Email Access to Full Account Compromise

Controlling someone's email is often the master key to their entire digital identity. Password reset links for banking, social media, and cloud services all flow through email. An attacker with SMTP access can trigger resets, intercept the confirmation emails, and lock the legitimate owner out of account after account. With 1,667 verified credentials, this collection enables a systematic campaign of identity takeover that extends far beyond simple credential stuffing.

The Cyberdataofficial Operation

The Cyberdataofficial label identifies an active threat actor operating through Telegram who specializes in distributing curated, validated credential sets. This actor uses infostealer malware to harvest login data from infected devices, then filters the results by service type — in this case, extracting credentials with working SMTP access. The malware targets browser credential stores, email client configurations, and application-specific password files. By selling pre-validated SMTP credentials, this operation enables downstream attackers to skip the testing phase and move directly to exploitation.

Check If Your Credentials Were Exposed

With over 400 billion records in its database, HEROIC's breach scanner provides extensive coverage of stealer logs, data breaches, and dark web credential dumps. Search your email address to check if your SMTP credentials were included in the Good SMTPs Cyberdataofficial collection. If your account appears, change your email password immediately, revoke any active sessions, and enable two-factor authentication to prevent unauthorized sending.