Onliner Spambot Uses List of 711 Million Email Accounts

Is your email address one of the 711 million emails that are being used by the Onliner spam-bot?  I checked my email address at Have I Been Pwned and found it on the list.  You can click through the link and see if yours is on the Onliner list, or part of some other breach.

Onliner is currently responsible for sending emails to spread a banking credential stealing exploit called Ursnif.  But spambots can be used for any number of purposes, including phishing, email account hijacking, sending malware laden attachments in email, website scanning, social engineering, stealing other account credentials, and sending click-fraud advertising spam.

This list is interesting because there are a couple components.  One list contains email accounts, passwords, and outbound mail server information that allows the phishing message to appear to come from legitimate email accounts, and that way, they get past many mail filters.

The second list contains millions of potential spam targets.  In a list this large many of the email addresses will be expired, out of date, or abandoned, so the first emails coming from this spam-bot are designed to confirm whether the account is active.  This is accomplished by sending a very small 1 pixel image in the email.  When you open the email, the image calls back to the image server with information such as your IP address, browser type and version, and other system information.

Once your email address is confirmed, then the attacker sends an email with the Ursnif banking Trojan as an email attachment.  In addition to stealing your online banking credentials, it can be used as a platform to install other malware.

What can you do?

  • Learn how to recognize phishing and other email exploits.
  • Never click on links or open attachments without verifying the link destination or attachment contents.  This can be done at VirusTotal.
  • Check your email accounts at Have I Been Pwned, and if you find your there, you may want to change your email password.
  • Protect your email, financial, and shopping accounts with two-factor authentication.

More information:


About the Author:

Cybersecurity analyst, pen-tester, trainer, and speaker. Owner of the WyzCo Group Inc. In addition to consulting on security products and services, Bob also conducts security audits, compliance audits, vulnerability assessments and penetration tests. Bob also teaches Cybersecurity Awareness Training classes. Bob works as an instruction for CompTIA’s non-profit IT-Ready Program in the Twin Cities. IT-Ready is a tuition free 8-week program designed to teach students of all ages the fundamentals of IT support to prepare them for an entry level position in Information Technology Support. Graduates of the classes take the exams to become CompTIA A+ certified. Bob is a frequent speaker at conferences such as the Minnesota Bloggers Conference, Secure360 Security Conference2016, 2017, 2018, 2019, the (ISC)2 World Congress 2016, and the ISSA International Conference 2017, and many local community organizations, including Chambers of Commerce, SCORE, and several school districts. Bob has been blogging on cybersecurity since 2006 at

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