Description

ConsentFix v3 is an emerging attack technique targeting Microsoft cloud environments like Microsoft Azure by abusing weaknesses in OAuth 2.0 authorization flows. It builds on earlier versions by automating phishing and token theft processes, making attacks more scalable and efficient. The method focuses on tricking users into completing legitimate authentication flows, allowing attackers to capture authorization codes and convert them into access and refresh tokens. Because it leverages trusted Microsoft applications and pre-consented permissions, it can bypass protections such as multi-factor authentication and avoid raising immediate suspicion. In the initial phase, attackers perform reconnaissance by identifying valid Azure tenants and collecting employee details like email addresses and roles. They then prepare infrastructure using services such as Cloudflare Pages and Pipedream to host phishing pages and automate workflows. Victims receive highly personalized phishing emails, often containing links embedded in documents, which redirect them to fake Microsoft login pages. These pages initiate a real authentication request, increasing credibility and reducing the likelihood of detection. In the exploitation phase, victims are tricked into copying or interacting with a localhost URL containing an OAuth authorization code. This code is sent to attacker-controlled systems, where automation tools instantly exchange it for tokens using Microsoft APIs. These tokens grant access to sensitive resources such as emails and files. Due to features like Family of Client IDs (FOCI), attackers may expand access across multiple Microsoft applications, increasing impact and persistence without needing repeated authentication. This attack highlights structural challenges in OAuth implementations and the risks of token-based access. Mitigation requires enforcing strict conditional access policies, enabling token binding to trusted devices, monitoring non-interactive sign-ins, and rapidly revoking refresh tokens when compromise is suspected. Organizations should also enhance phishing detection, limit unnecessary app permissions, and continuously audit authentication activity to reduce exposure to such advanced threats.