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🎭 The #Attack With a Real Login Page
This technique is called #device code phishing, or OAuth device code flow abuse.
It abuses the #OAuth 2.0 device authorization grant, originally designed for devices with limited input, like smart TVs, IoT devices, and CLI tools. The device shows a code, the user visits a verification URL, enters the code, and authenticates the device.
Microsoft implements this at microsoft.com/devicelogin.
Attackers weaponize that trust. They initiate a legitimate device code request against Microsoft’s identity platform, often impersonating apps like Microsoft Office, Teams, or Azure CLI. Microsoft returns a real code, usually valid for around 15 minutes. The victim is then asked to "verify their identity" or "join a Teams meeting" by entering that code on Microsoft’s real login page.
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🧨 Why #MFA Still Passed
When the user completes the flow, they are not logging into their own session. They are authorizing the attacker’s session.
#Microsoft then issues access and refresh tokens to the attacker-controlled polling endpoint. Those tokens can provide access to mailboxes, SharePoint, Teams, and federated apps.
MFA passes because the user genuinely authenticated. Conditional Access may pass because the interaction appears to come from the user’s real device and location. Anti-phishing training fails because there is no fake domain to spot.
Microsoft has reported active device code phishing campaigns by Storm-2372, a threat actor assessed as likely aligned with Russian interests, active since August 2024 and observed targeting organizations through 2025.
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🛡️ The Fix Is #Configuration, Not More Posters
Block device code flow by default in Entra ID using Conditional Access authentication flow controls. Allow it only for specific users, apps, or scenarios that truly need it, such as kiosks or legacy CLI workflows.
Then alert on every successful device code authentication. In most environments, this should be rare, predictable, and easy to investigate.
- logisek.com
#CyberSecurity #RedTeam #PenTest #InfoSec #OffSec #SecurityMindset #OffensiveSecurity #CloudSecurity #IdentitySecurity #Logisek

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