OnlinerSpambot

Last reviewed: October 27, 2026

OnlinerSpambot

OnlinerSpambot is a malware campaign primarily used for sending spam emails. It is known for its extensive database of email addresses and credentials, which it uses to distribute spam and potentially malicious content. The malware has been active since at least 2016 and has been linked to various cybercriminal activities, including the distribution of banking trojans. OnlinerSpambot operates by compromising email accounts and using them to send out large volumes of spam emails, often containing malicious attachments or links.

Overview

OnlinerSpambot is a spamming operation that leverages a vast database of compromised email credentials to send spam emails on a massive scale. The primary objective of OnlinerSpambot is to distribute spam emails, which may include phishing attempts or malware-laden attachments. The malware is notable for its ability to evade detection and its use of compromised email accounts to bypass spam filters.

History

OnlinerSpambot was first identified in 2016, although its origins may date back earlier. The malware gained significant attention in 2017 when a security researcher discovered a massive database associated with the campaign. This database contained over 700 million email addresses and passwords, making it one of the largest data breaches of its kind at the time. The discovery highlighted the scale and potential impact of the OnlinerSpambot operation.

Technical characteristics

OnlinerSpambot is designed to send spam emails using compromised email accounts. It operates by accessing a database of stolen email credentials and using them to log into email accounts. Once access is gained, the malware sends out spam emails to contacts in the victim's address book or other targeted lists. The spam emails often contain malicious attachments or links designed to infect recipients' systems with additional malware.

The malware is capable of evading detection by using legitimate email accounts to send spam, which helps it bypass traditional spam filters. Additionally, OnlinerSpambot employs various techniques to avoid detection, such as rotating email accounts and using different IP addresses.

Infection vector

OnlinerSpambot primarily spreads through phishing emails and compromised websites. Cybercriminals use phishing emails to trick recipients into providing their email credentials, which are then added to the OnlinerSpambot database. In some cases, the malware may also be distributed through malicious attachments or links in spam emails.

Once a system is compromised, the malware can harvest email credentials and add them to its database, further expanding its reach and effectiveness.

Notable campaigns

OnlinerSpambot has been linked to several notable campaigns, particularly those involving the distribution of banking trojans. One such campaign involved the distribution of the Ursnif banking trojan, which is designed to steal sensitive financial information from infected systems. The use of OnlinerSpambot in these campaigns highlights its role as a tool for distributing other types of malware.

Detection and mitigation

Detecting OnlinerSpambot can be challenging due to its use of legitimate email accounts for sending spam. However, organizations can implement several measures to mitigate the risk of infection. These include:

Implementing strong email security measures, such as multi-factor authentication, to protect email accounts from being compromised.
Educating users about the risks of phishing emails and how to recognize them.
Regularly updating and patching systems to protect against known vulnerabilities.
Using advanced email filtering solutions to detect and block spam emails.

By taking these steps, organizations can reduce the risk of falling victim to OnlinerSpambot and other similar malware campaigns.

Sources

Categories: Threat Actors | Malware

Last updated: October 27, 2026