[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"$frFeGKTymWziQ6etuMkdaSMq_VPVUR9oRbe8dJ3tX0-8":3},{"lesson":4},{"id":5,"slug":6,"article_id":7,"title":8,"body":9,"prevention":10,"framework_refs":11,"status":21,"created_at":22,"published_at":23,"article":24,"tags":28,"podcasts":47},"4a525aa4-7667-4db8-a123-43cf87a0399d","hidden-prompts-in-word-docs-manipulate-microsoft-copilot-output","05c0e8c8-bcc0-439d-b640-5244cd44db80","Hidden Prompts in Word Docs Manipulate Microsoft Copilot Output","This vulnerability exploits a prompt injection technique, where malicious instructions hidden within a Word document hijack Microsoft 365 Copilot's AI behavior, causing it to silently alter document content such as financial figures and then propagate the hidden instructions into newly generated documents. The root issue lies in the AI model's inability to reliably distinguish between trusted user instructions and untrusted content embedded in processed documents. This matters because users may unknowingly trust AI-generated summaries or reports that have been silently tampered with, creating serious risks for business decisions, financial reporting, and document integrity. The self-propagating nature of the embedded prompts also means the attack can spread across an organization's document ecosystem without detection.","**Immediate actions:**\n- Treat all AI-generated document outputs as unverified until cross-checked against original source data, especially for figures and key facts.\n- Review and restrict which external or user-submitted documents are permitted as input to Microsoft 365 Copilot workflows.\n- Apply all available Microsoft mitigations and monitor the vendor's security advisories for updated patches addressing this vulnerability class.\n\n**Long-term improvements:**\n- Establish an AI usage policy that defines acceptable use cases for Copilot and mandates human review of AI-modified documents before distribution.\n- Implement document provenance controls to track when and how AI tools have modified content, maintaining an audit trail for sensitive documents.\n- Conduct regular red-team exercises specifically targeting AI-integrated tools to identify prompt injection and content manipulation risks.\n\n**Detection measures:**\n- Enable logging of all Microsoft 365 Copilot interactions and integrate those logs into your SIEM for anomaly detection.\n- Deploy content-integrity checks on documents that pass through AI processing pipelines to flag unexpected modifications to numerical or critical data fields.\n- Train employees to recognize signs of AI output manipulation, such as inconsistencies between source documents and AI-generated summaries.",[12,13,14,15,16,17,18,19,20],"NIST AI RMF: GOVERN 1.2 – Policies for AI risk management","NIST SP 800-53 SI-10 – Information Input Validation","NIST SP 800-53 AU-2 – Audit Events \u002F Logging","CIS Control 3 – Data Protection","CIS Control 7 – Continuous Vulnerability Management","CIS Control 8 – Audit Log Management","MITRE ATLAS AML.T0051 – Prompt Injection","GDPR Article 5(1)(f) – Integrity and Confidentiality of personal data","ISO\u002FIEC 42001 – AI Management System Standard","published","2026-07-30T14:21:02.441977+00:00","2026-07-30T14:21:02.331+00:00",{"id":7,"url":25,"slug":26,"title":27},"https:\u002F\u002Fthehackernews.com\u002F2026\u002F07\u002Fmicrosoft-copilot-for-word-can-copy.html","microsoft-copilot-for-word-can-copy-hidden-prompts-into-new-documents-691699","Microsoft Copilot for Word Can Copy Hidden Prompts Into New Documents",[29,35,41],{"id":30,"name":31,"slug":32,"description":33,"color":34},"05757c8d-6b93-4194-b35d-7359e7d33b0e","Vulnerability Management","vulnerability-management","Missing scans, no risk prioritization","#fb923c",{"id":36,"name":37,"slug":38,"description":39,"color":40},"7261eb8f-acd4-4d93-a489-7fdd652ec0ea","Security Awareness","security-awareness","Phishing, social engineering, human error","#22c55e",{"id":42,"name":43,"slug":44,"description":45,"color":46},"859cf0ad-a7e9-42bb-a75d-bac6511fa5d5","Configuration Management","configuration-management","Misconfigs, default credentials, exposed services","#eab308",[]]