Signal

Hijacked outlook add-in reportedly used to steal 4,000+ microsoft credentials

Evidence first: scan the strongest sources, then decide whether to go deeper.

Published 2026-02-11 17:45 UTCUpdated 2026-02-11 21:53 UTC
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phishingcredential_theftsupply_chainmicrosoftoutlookmalicious_addin
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Evidence trail (top sources)
top sources (2 domains)domains are deduped. counts indicate coverage, not truth.
2 top sources shown
limited source diversity in top sources
Overview

Two security news outlets report on research from Koi Security alleging a supply-chain style compromise of a Microsoft Outlook add-in: an attacker took control of a domain tied to an abandoned legitimate add-in and used it to present a fake Microsoft login flow, resulting in large-scale credential theft.

Entities
MicrosoftKoi SecurityMicrosoft OutlookAgreeTo
Score total
1.01
Momentum 24h
2
Posts
2
Origins
2
Source types
1
Duplicate ratio
0%
Why now
  • Multiple outlets are amplifying Koi Security’s findings
  • Reports describe in-the-wild activity with a quantified credential-theft impact
Why it matters
  • Shows how trusted Outlook add-ins can be abused for credential phishing
  • Highlights risk from abandoned add-ins and takeover of associated domains
  • Stolen Microsoft credentials can enable broader account compromise
LLM analysis
Topic mix: lowPromo risk: lowSource quality: medium
Recurring claims
  • Koi Security says an attacker claimed a domain linked to an abandoned legitimate Outlook add-in and used it to serve a fake Microsoft login page.
  • The hijacked AgreeTo Outlook add-in was reportedly used as a phishing kit to steal more than 4,000 Microsoft account credentials.
How sources frame it
  • The Hacker News: neutral
  • BleepingComputer: neutral
Reports describe a domain-takeover style supply-chain abuse of an Outlook add-in leading to credential phishing.
All evidence
All evidence
Microsoft Store Outlook add-in hijacked to steal 4,000 Microsoft accounts
bleepingcomputer_all · bleepingcomputer.com · 2026-02-11 21:53 UTC
First Malicious Outlook Add-In Found Stealing 4,000+ Microsoft Credentials
thehackernews · thehackernews.com · 2026-02-11 17:45 UTC
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Posts loaded: 0Publishers: 2Origin domains: 2Duplicates: -
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Top publishers (this list)
  • bleepingcomputer_all (1)
  • thehackernews (1)
Top origin domains (this list)
  • bleepingcomputer.com (1)
  • thehackernews.com (1)