Russia-Linked APT28 Exploits MDaemon Zero-Day to Target Government Webmail Servers
May 15, 2025
Vulnerability / Email Security
A cyber espionage operation associated with a Russian threat actor is reportedly compromising webmail servers, including Roundcube, Horde, MDaemon, and Zimbra, by exploiting cross-site scripting (XSS) vulnerabilities, notably a zero-day flaw in MDaemon. This activity, coded as Operation RoundPress by ESET, began in 2023 and has been linked with moderate confidence to the state-sponsored hacking group APT28, also known by various names such as BlueDelta, Fancy Bear, and Sednit.
“The primary objective of this operation is to extract sensitive data from targeted email accounts,” stated ESET researcher Matthieu Faou in a report shared with The Hacker News. “While most victims are governmental and defense entities in Eastern Europe, we have also noted targets across Africa, Europe, and beyond.”