MICROSOFT EXCHANGE SERVER · CMP-202611-qduyyn · Vendor
NO FIX YET · SEE WHAT TO DO
ESET found Cereal, a new modular .NET toolset used by the Russia-aligned (FSB-linked) Turla group to turn Microsoft Exchange servers into long-term email collection points. Confirmed victims: a national government organization in Kazakhstan (found 28 Nov 2025) and one in Romania (compromised 23 Dec 2025), where it was set to collect mail involving NATO and EU addresses. The backdoor CerealNeuron has no external command server: it listens on the Exchange server for encrypted requests on paths that look like normal Exchange traffic (Outlook Web Access, Autodiscover, ActiveSync) and runs compiled .NET programs sent to it. CerealBox is injected into EdgeTransport.exe and hijacks transport agents already loaded in memory, so no new transport agent shows up in Exchange's configuration. It copies emails with DOC, DOCX or PDF attachments that match hardcoded sender, recipient, subject or attachment-name lists. The commands can pull mailboxes, query Active Directory, run WMI queries, extract LSA secrets and handle files. How the attackers got in: unknown. Ingress IPs: unknown.
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first public Nov 8, 2026 · 1 posts · 1 source
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