Last updated: September 29, 2026 at 8:42 AM UTC
All 891 Vulnerability 357 Breach 144 Threat 383 Defense 7
Tag: microsoft-365 (15 articles)Clear

FBI warns of Kali365 phishing-as-a-service: OAuth device-code consent abuse against Microsoft 365 since April, $250-$2,000/year

The FBI has issued a warning about Kali365, a phishing-as-a-service platform that fueled large Microsoft 365 attacks in April. Instead of stealing passwords, Kali365 customers trigger Microsoft device-login requests and trick victims into completing the authorization, capturing OAuth access and refresh tokens that grant immediate mailbox access. Arctic Wolf, which infiltrated the system, says Kali365 sells in three tiers from $250 for 30 days to $2,000 for the year and generates branded phishing lures impersonating Adobe, DocuSign, and SharePoint in dozens of languages. Threat actors set malicious inbox rules to suppress security notifications and extend dwell time.

Check
Search Microsoft 365 audit logs for unfamiliar device-login completions and OAuth consent grants since April 1. Hunt for inbox rules that auto-delete or hide security-team email addresses.
Affected
Any Microsoft 365 tenant where users can complete device-login flows initiated by an attacker. Adobe, DocuSign, and SharePoint-themed lures are the primary social engineering vector.
Fix
Block device-code flow in Conditional Access for non-mobile platforms. Enforce phishing-resistant FIDO2 MFA. Train users to verify the device-login codes they approve. Audit OAuth-granted apps quarterly.

Storm-2949 abuses Microsoft 365 Self-Service Password Reset to hijack accounts, pivot from M365 into Azure production

Microsoft is tracking a financially motivated actor it calls Storm-2949 that abuses the Microsoft 365 Self-Service Password Reset flow to hijack high-value identities and then exfiltrate as much data as possible. The actor socially engineers IT staff and senior leaders, kicks off an SSPR reset, then poses as IT support and convinces the victim to approve the resulting MFA prompt. Once in, Storm-2949 uses Graph API and custom Python to enumerate the tenant, downloads thousands of OneDrive and SharePoint files in single actions, and pivots into Azure - VMs, Key Vaults, SQL, storage - via privileged custom RBAC roles.

Check
In Entra audit logs, find users who reset their password and within 24 hours added or had MFA removed. Pull Graph API calls enumerating users and service principals from new IPs.
Affected
Microsoft 365 tenants with SSPR enabled where help-desk identity is not strongly authenticated. High-privilege custom Azure RBAC roles assigned broadly amplify blast radius.
Fix
Require ticket-based identity verification for SSPR resets on admin and exec accounts. Enforce phishing-resistant FIDO2 MFA. Tighten custom-role assignments. Alert on mass OneDrive downloads via Defender for Cloud.

Tycoon2FA pivots to OAuth device-code phishing - lures Microsoft 365 users to legitimate microsoft.com/devicelogin

The Tycoon 2FA phishing-as-a-service kit, which Microsoft, Europol, Cloudflare and others tried to dismantle in March 2026, is back and has switched tactics. Instead of relaying credentials and MFA codes through a fake login page, operators now send victims to Microsoft's legitimate device-login page at microsoft.com/devicelogin and ask them to enter a code from the lure email. That single consent grants the attacker OAuth tokens for the victim's Exchange Online, OneDrive, and SharePoint through Microsoft's own Authentication Broker app, so it looks normal in Entra logs. eSentire spotted the late-April campaign and published IoCs, including AS45102 (Alibaba Cloud) operator infrastructure.

Check
Search Entra sign-in logs for Microsoft Authentication Broker consents (AppId 29d9ed98-a469-4536-ade2-f981bc1d605e) from unfamiliar IPs, especially AS45102 (Alibaba Cloud) with node/undici user agents.
Affected
Microsoft 365 tenants without Conditional Access policies restricting the OAuth Device Authorization Grant flow. The initial lure abuses legitimate Trustifi click-tracking URLs.
Fix
Block the Device Code Flow in Conditional Access for users who do not need it (most knowledge workers do not). Review eSentire IoCs and revoke matching sessions and refresh tokens.

New 'ConsentFix v3' attack lets criminals take over Microsoft 365 accounts even when MFA and passkeys are turned on

Push Security disclosed ConsentFix v3, a new attack that lets criminals take over Microsoft 365 accounts even if the victim has MFA and phishing-resistant passkeys turned on. The trick: instead of stealing a password, the attacker tricks the user into pasting a Microsoft authorization URL into a phishing page during what looks like a routine login. That URL contains a one-time code that the attacker exchanges for permanent access tokens. v3 automates the whole attack with Cloudflare Pages phishing sites, Pipedream webhook automation, and tenant fingerprinting that customizes the lure to each target organization's branding.

Check
Brief any Microsoft 365 admin or developer that any 'verification step' that asks them to paste a URL containing 'localhost' into a webpage is hostile, no matter how legitimate the page looks.
Affected
Any Microsoft 365 / Entra ID tenant. The attack bypasses MFA, passkeys, and most Conditional Access policies by abusing pre-consented Microsoft first-party apps. Acute risk for organizations whose admins, developers, or DevOps engineers regularly use Azure CLI - those users won't suspect a fake Azure CLI authorization page. Cloudflare Pages and Pipedream both look legitimate in network telemetry.
Fix
Apply token binding to trusted devices and require Conditional Access for first-party Microsoft apps where possible. Hunt Azure sign-in logs for Azure CLI authentications from unfamiliar IPs, especially against accounts that don't normally use it. Train developers to verify out-of-band any 'verification step' that asks them to paste URLs into a webpage. Use app authentication restrictions to limit which first-party apps can issue refresh tokens.

FBI and Indonesian police dismantle W3LL phishing platform that powered business email compromise attacks worldwide

The FBI Atlanta Field Office and Indonesian authorities have dismantled the W3LL global phishing platform and arrested its alleged developer. W3LL sold a sophisticated phishing kit designed specifically for bypassing multi-factor authentication on Microsoft 365 accounts using adversary-in-the-middle (AiTM) techniques. The platform operated as a phishing-as-a-service ecosystem with its own marketplace, support channels, and licensing model, enabling thousands of business email compromise campaigns targeting corporate Microsoft 365 environments. This is described as the first coordinated international law enforcement action against this platform. Group-IB previously estimated W3LL's tools had been used to compromise over 8,000 Microsoft 365 business accounts.

Check
Review your Microsoft 365 security configuration. W3LL's kit was specifically designed to bypass standard MFA on M365 - organizations relying solely on push notification or SMS-based MFA for M365 were the primary targets.
Affected
Organizations using Microsoft 365 with standard MFA (push notifications, SMS codes, or authenticator app approval prompts). W3LL's AiTM technique proxied real login pages to intercept session tokens after MFA completion.
Fix
Deploy phishing-resistant MFA for Microsoft 365 - FIDO2 security keys or Windows Hello for Business are resistant to AiTM attacks. Enable conditional access policies that evaluate sign-in risk, device compliance, and location. Monitor for suspicious mailbox rules (forwarding, deletion rules) which are the first post-compromise action in BEC campaigns. The W3LL takedown disrupts one platform, but the AiTM phishing technique is now widely adopted by other kits.