Nation-state APTs ramp up attacks on Ukraine and the EU

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.

CVE-2024-49039 is an elevation-of-privilege vulnerability (CWE-287, improper authentication) in the Microsoft Windows Task Scheduler, scored 8.8 (High) with a local attack vector, low required privileges, and a changed scope indicating the exploit crosses a security boundary. A local attacker with limited user privileges can trigger the flaw through Task Scheduler to gain elevated rights on the affected system, typically SYSTEM- or administrator-level control, with no user interaction required. Every supported Windows desktop and server release in the vendor's affected list is impacted, since Task Scheduler is a core component of the operating system. The flaw was patched as an actively exploited zero-day in the November 2024 Patch Tuesday release, was added to CISA's Known Exploited Vulnerabilities catalog on 2024-11-12, and ransomware operators are known to use it. With an EPSS of 14.2% (96th percentile), defenders should treat this as a high-priority local privilege escalation for privilege-chaining and ransomware campaigns.

Do: Apply the November 2024 Windows security updates across all affected Windows 10, Windows 11, and Windows Server branches, prioritizing servers, jump hosts, and machines used by privileged users given confirmed ransomware use. Confirm no supported Windows host is left unpatched, review local task creation and authentication logs for signs of privilege escalation, and follow CISA's required action to apply vendor mitigations or discontinue use if patches are unavailable.

Mozilla Firefox and Firefox ESR contain a use-after-free (CWE-416) in the browser's animation timelines component, which CISA describes as allowing code execution in the content process. The flaw is reachable through malicious web content: a crafted page can manipulate animation timelines so that an in-use object is freed, producing exploitable memory corruption. A successful attacker gains code execution in the content process, the sandboxed process that renders web pages, on the machine of the user who loaded the content. All users of Firefox and Firefox ESR are affected by the flaw itself. It is being actively exploited: the vulnerability was added to CISA's Known Exploited Vulnerabilities catalog on 2024-10-15 with known ransomware use, and EPSS assigns it a 23.2% probability of exploitation in the next 30 days (98th percentile).

Do: Apply Mozilla's patched Firefox/Firefox ESR release immediately and verify the running version via the browser's About Firefox dialog, since many installs only pick up auto-updates after a restart (per CISA's required action: apply mitigations per vendor instructions or discontinue use). Given the known ransomware use, prioritize enterprise ESR rollout and check for managed-update failures, auto-update-disabled installs, or unmanaged Firefox copies on user machines. Note that no public proof-of-concept is known, but KEV listing confirms exploitation, so patching should not wait for PoC availability.