[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$fBW1ID9vb22w2tEwIPASQOGuOjjFpvuNwilN3yzW5NxA":3},{"article":4,"iocs":40},{"id":5,"title":6,"slug":7,"summary":8,"ai_summary":9,"brief":10,"full_text":11,"url":12,"image_url":11,"published_at":13,"ingested_at":14,"relevance_score":15,"entities":16,"category_id":23,"category":24,"article_tags":27},"318967f6-03d2-4f66-9226-b8028411d445","Researchers Uncover HOLLOWGRAPH: Malware That Hides Inside Microsoft 365 Calendar Invites","researchers-uncover-hollowgraph-malware-that-hides-inside-microsoft-365-calendar-e793f6","A previously undocumented strain of Windows malware is using Microsoft 365 calendar invites as a covert communications channel, allowing attackers to issue commands and exfiltrate stolen files from victim networks while hiding in plain sight among ordinary enterprise traffic, according to new research from the threat intelligence firm Group-IB. The malware, dubbed HOLLOWGRAPH, was detailed […] The post Researchers Uncover HOLLOWGRAPH: Malware That Hides Inside Microsoft 365 Calendar Invites appeared first on IT Security Guru.","Researchers have discovered a new Windows malware strain named HOLLOWGRAPH that leverages Microsoft 365 calendar invites as a covert channel for command and control (C2) and data exfiltration. This sophisticated technique allows attackers to blend malicious communications with legitimate enterprise traffic, making detection significantly more challenging. Group-IB's research highlights the novel use of a common productivity tool for malicious purposes.","New HOLLOWGRAPH malware uses Microsoft 365 calendar invites for C2 and data exfiltration.",null,"https:\u002F\u002Fwww.itsecurityguru.org\u002F2026\u002F07\u002F20\u002Fresearchers-uncover-hollowgraph-malware-that-hides-inside-microsoft-365-calendar-invites\u002F?utm_source=rss&utm_medium=rss&utm_campaign=researchers-uncover-hollowgraph-malware-that-hides-inside-microsoft-365-calendar-invites","2026-07-20T10:32:41+00:00","2026-07-20T11:03:00.976427+00:00",8,[17,20],{"name":18,"type":19},"Microsoft 365","product",{"name":21,"type":22},"Group-IB","vendor","89f78b1c-3503-45a1-9fc7-e23d2ce1c6d5",{"id":23,"icon":11,"name":25,"slug":26},"Malware","malware",[28,33,35],{"category":29},{"id":30,"icon":11,"name":31,"slug":32},"26b0b636-0e31-4db1-bffb-61bdf9f20a58","Supply Chain","supply-chain",{"category":34},{"id":23,"icon":11,"name":25,"slug":26},{"category":36},{"id":37,"icon":11,"name":38,"slug":39},"e7b231c8-5f79-4465-8d38-1ef13aea5a14","Threat Intelligence","threat-intelligence",[]]