Russia-linked hackers target webmail servers in Ukraine-related espionage operation
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2023-43770 | Persistent Cross-Site Scripting in Roundcube Webmail (Exploited in the Wild) Roundcube Webmail versions before 1.4.14, 1.5.x before 1.5.4, and 1.6.x before 1.6.3 contain a persistent cross-site scripting (XSS) flaw (CWE-79) caused by how program/lib/Roundcube/rcube_string_replacer.php converts plain text into clickable links. An attacker sends a text/plain email containing crafted links; when the recipient views the message, the crafted link text is turned into HTML that runs attacker-controlled script, which persists and executes in the victim's webmail session. Successful exploitation lets the attacker execute JavaScript with the victim's session, enabling mailbox access, theft of session credentials, and actions performed as the user (CVSS 6.1, scope-changed with limited confidentiality and integrity impact). Anyone running an affected Roundcube instance is exposed, including the roundcube package shipped with Debian Linux. The flaw is being actively exploited: CISA added it to the Known Exploited Vulnerabilities catalog on 2024-02-12, and EPSS assigns a 58.5% probability of exploitation within 30 days (99th percentile). Do: Upgrade Roundcube to 1.4.14, 1.5.4, or 1.6.3 (or later, per branch), or install the updated roundcube package on Debian. Because the bug is in CISA's KEV catalog, U.S. federal agencies must apply the vendor fix by the catalog due date, and other defenders should prioritize patching internet-facing webmail servers. Review webmail access logs for suspicious message views or account activity, and consider forcing session re-authentication for accounts that opened crafted plain-text messages. | 6.1 | 58% | KEV |
| massplausibly millions of users across tens of thousands of internet-exposed Roundcube instances (estimate) | |
| CVE-2024-11182 | Unauthenticated Cross-Site Scripting (XSS) in MDaemon Email Server Webmail MDaemon Email Server versions before 24.5.1c contain a cross-site scripting flaw (CWE-79) in its handling of HTML email: JavaScript embedded in an img tag is not properly sanitized. A remote, unauthenticated attacker can trigger it simply by sending a crafted HTML email that a webmail user then opens, requiring no privileges but relying on user interaction. Successful exploitation loads attacker-supplied JavaScript in the context of the webmail user's browser window, which could enable session or credential theft and further intrusions from that user's session. Any organization running an affected MDaemon version with users of its webmail client is affected; MDaemon is a commercial on-premises Windows mail server used mainly by small and mid-sized organizations. The flaw is being actively exploited: CISA added it to the Known Exploited Vulnerabilities catalog on 2025-05-19, and public reporting ties MDaemon exploitation to Russia-linked APT28 (Fancy Bear) campaigns that targeted the email of high-level Ukrainians and their military suppliers. Do: Upgrade to MDaemon Email Server 24.5.1c or later, prioritizing installations whose webmail is exposed to the internet, since the flaw is actively exploited and KEV-listed. Review webmail access and message-viewing logs for suspicious activity, especially in organizations that may be targeted by APT28 (Ukrainian government, military, or defense-supply interests). Federal agencies must follow CISA KEV required actions (apply vendor mitigations per instructions and applicable BOD 22-01 guidance, or discontinue use if mitigations are unavailable) by the required due date. | 5.3 | 18% | KEV |
| moderatetens of thousands of on-premises deployments; plausibly on the order of 10,000–100,000 webmail users |
Full article535 words · extracted from helpnetsecurity.com · click to collapse
ESET researchers have uncovered RoundPress, a Russia-aligned espionage operation targeting webmail servers via XSS vulnerabilities. Behind it is most likely the Russia-aligned Sednit (also known as Fancy Bear or APT28) cyberespionage group, holding the ultimate goal of stealing confidential data from specific email accounts.
Operation RoundPress compromise chain (Source: ESET)
Targets
Most of the targets are related to the current war in Ukraine. They are either Ukrainian governmental entities or defense companies in Bulgaria and Romania. Notably, some of these defense companies are producing Soviet-era weapons to be sent to Ukraine. Other targets include African, EU, and South American governments.
“Last year, we observed different XSS vulnerabilities being used to target additional webmail software: Horde, MDaemon, and Zimbra. Sednit also started to use a more recent vulnerability in Roundcube (CVE-2023-43770). The MDaemon vulnerability — CVE-2024-11182, now patched — was a zero day, most likely discovered by Sednit, while the ones for Horde, Roundcube, and Zimbra were already known and patched,” says ESET researcher Matthieu Faou, who discovered and investigated Operation RoundPress.
How the exploit works
Sednit sends these XSS exploits by email. They lead to the execution of malicious JavaScript code in the context of the webmail client web page running in a browser window. Only data accessible from the target’s account can be read and exfiltrated.
In order for the exploit to work, the target must be convinced to open the email message in the vulnerable webmail portal. This means that the email needs to bypass any spam filtering, and the subject line needs to be convincing enough to entice the target into reading the email message — abusing well-known news media such as Ukrainian news outlet Kyiv Post or Bulgarian news portal News.bg. Among the headlines used as spearphishing were: “SBU arrested a banker who worked for enemy military intelligence in Kharkiv” and “Putin seeks Trump’s acceptance of Russian conditions in bilateral relations”.
The attackers unleash JavaScript payloads SpyPress.HORDE, SpyPress.MDAEMON, SpyPress.ROUNDCUBE, and SpyPress.ZIMBRA upon the targets. Those are capable of credential stealing; exfiltration of the address book, contacts, and log-in history; and exfiltration of email messages. SpyPress.MDAEMON is able to set up a bypass for two-factor authentication protection; it exfiltrates the two-factor authentication secret and creates an app password, which enables the attackers to access the mailbox from a mail application.
“Over the past two years, webmail servers such as Roundcube and Zimbra have been a major target for several espionage groups, including Sednit, GreenCube, and Winter Vivern. Because many organizations don’t keep their webmail servers up to date, and because the vulnerabilities can be triggered remotely by sending an email message, it is very convenient for attackers to target such servers for email theft,” explains Faou.
Behind the hacks
The Sednit group — also known as APT28, Fancy Bear, Forest Blizzard, or Sofacy — has been operating since at least 2004. The U.S. Department of Justice named the group as one of those responsible for the Democratic National Committee (DNC) hack just before the 2016 U.S. elections and linked the group to the GRU. The group is also presumed to be behind the hacking of global television network TV5Monde, the World Anti-Doping Agency (WADA) email leak, and many other incidents.
Text extracted automatically; images, tables and formatting may be missing. Original: https://www.helpnetsecurity.com/2025/05/15/espionage-operation-roundpress-webmail-servers/