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Introduction: A New Kind of Identity Threat
In December, security researchers uncovered a quietly dangerous attack technique that reshapes how account takeovers can happen in modern cloud environments. Named ConsentFix, this method blends social engineering with OAuth abuse to bypass passwords, MFA, and even phishing-resistant authentication. Unlike traditional phishing, this attack lives entirely inside the browser and exploits trusted Microsoft application flows, making it both subtle and extremely effective. What began as a single discovery quickly escalated into a large-scale campaign, community-wide analysis, and growing concern among defenders responsible for protecting Microsoft Entra ID and Azure environments.
ConsentFix at a Glance
ConsentFix is a novel attack technique that tricks victims into sharing an OAuth authorization code with an attacker. Once obtained, the attacker completes the authentication flow on their own device, effectively logging in as the victim without ever needing credentials. This approach sidesteps the identity layer entirely, rendering many traditional defenses irrelevant.
Discovery of the Campaign
The technique was first identified by the Push Security research team, who detected it being actively deployed across a wide network of compromised websites. Attackers injected malicious payloads into legitimate pages, enabling them to scale the attack across multiple organizations simultaneously. The campaign was observed impacting several customer environments before it was blocked.
Community Reaction and Rapid Evolution
The disclosure of ConsentFix triggered an unusually fast and collaborative response from the security community. Researchers from Microsoft, Glueck Kanja, and independent analysts shared detections, mitigations, and architectural insights. Within days, improved variants of the technique were already being demonstrated in controlled lab environments.
ConsentFix 101: How the Attack Works
At its core, ConsentFix abuses OAuth authorization flows. Victims are lured to a phishing page that asks them to “verify” their humanity. When they click a sign-in button, they are redirected to a legitimate Microsoft login page. If already logged in, no credentials are required. After account selection, Microsoft redirects the browser to a localhost URL containing an OAuth authorization code, which the victim is instructed to copy and paste back into the phishing page.
Why OAuth Makes This Dangerous
OAuth was designed to allow applications to securely access resources without exposing passwords. ConsentFix turns this strength into a weakness. Because the authentication step happens on Microsoft’s infrastructure, MFA and passkeys do not protect against the final handoff of the authorization code. The attacker simply completes the process on their own machine.
Bypassing Modern Identity Controls
One of the most alarming aspects of ConsentFix is its ability to bypass Conditional Access policies. By targeting first-party Microsoft applications that are pre-consented across tenants, attackers avoid admin approval workflows entirely. This makes the attack viable even in hardened enterprise environments.
A Shift from Traditional OAuth Phishing
Earlier OAuth attacks focused on tricking users into granting access to malicious third-party apps. ConsentFix flips the model by abusing trusted Microsoft-owned applications instead. This removes many of the friction points defenders rely on to detect suspicious consent grants.
The Role of Legacy Scopes
Attackers deliberately selected legacy OAuth scopes that fall outside default logging configurations. This allowed the activity to evade detection even when security teams reviewed sign-in and audit logs. In many cases, organizations had no visibility into the compromise at all.
Campaign Walkthrough: Step by Step
Victims are first presented with a verification page. Clicking “Sign In” opens a legitimate Microsoft login window. After account selection, the browser redirects to a localhost address containing the authorization code. The victim copies this URL and submits it back to the attacker-controlled page, unknowingly handing over session access.
Azure CLI as a Primary Target
The attackers primarily targeted Azure CLI, a command-line tool used to manage Entra ID and Azure resources. By authenticating as the victim inside Azure CLI, attackers gained broad administrative visibility and control depending on the victim’s permissions.
Manual Authorization, Automated Impact
While the flow requires user interaction, the attacker’s role is largely passive. Once the authorization code is received, it can be exchanged for access or refresh tokens, enabling persistent access without further victim involvement.
New Intelligence Emerges
As tracking continued, additional evidence suggested links between the ConsentFix campaign and Russian state-affiliated threat actors, specifically APT29. Researchers noted the stealth, patience, and sophistication of the operation as indicators of nation-state involvement.
Connection to Previous Russian Campaigns
ConsentFix appears to be an evolution of earlier manual OAuth abuse techniques documented by Volexity. In those cases, victims were socially engineered into emailing authorization codes directly. ConsentFix streamlines the process through browser-based automation.
Why This Isn’t Commodity Phishing
Unlike mass credential phishing, ConsentFix relies on precise targeting and trusted application flows. This places it firmly outside the realm of low-effort cybercrime and aligns it more closely with advanced persistent threat operations.
Vendor Noise vs. Real Defense
Following disclosure, many vendors rushed to publish marketing-driven responses. Some promoted endpoint detection tools that are fundamentally incapable of detecting browser-native OAuth abuse, creating confusion for defenders seeking real solutions.
Meaningful Contributions from Researchers
Amid the noise, several high-value contributions stood out. Independent researchers published app inventories, logging recommendations, and attack simulations that significantly advanced understanding of the threat.
ConsentFix Version 2.0
Security researcher John Hammond demonstrated an enhanced version of ConsentFix that made the attack smoother and more convincing. His version allowed victims to drag and drop the authorization URL directly into the phishing page, further reducing friction.
Speed of Iteration
The rapid appearance of improved variants highlighted how quickly attackers can refine browser-native techniques. What took days in a lab could take weeks or months to be fully mitigated in enterprise environments.
Expanded List of Vulnerable Apps
Researchers from Glueck Kanja identified 11 Microsoft first-party applications vulnerable to ConsentFix. These included Azure PowerShell, Microsoft Teams, Visual Studio, SharePoint Management Shell, and Visual Studio Code, among others.
Conditional Access Blind Spots
Each of these applications either had known Conditional Access exclusions or relied on legacy scopes. This created predictable gaps that attackers could reliably exploit across tenants.
The Growing Attack Surface
As organizations adopt more Microsoft tooling, the number of potential ConsentFix entry points increases. Every trusted app becomes a possible bridge into the identity plane.
Detection Challenges
Traditional EDR, network monitoring, and email security provide little value against ConsentFix. The attack occurs entirely within legitimate browser sessions, using trusted domains and workflows.
Logging Limitations
Many Microsoft tenants do not enable deprecated AADGraphActivityLogs by default. Without these logs, ConsentFix activity may be completely invisible during post-incident investigations.
Community-Driven Mitigations
Researchers recommended hunting for specific application IDs, resource IDs, and unusual OAuth flows. Creating service principals and restricting access to high-risk apps can significantly reduce exposure.
Browser as the New Battleground
ConsentFix reinforces a broader shift in attacker behavior. Identity attacks are increasingly browser-native, exploiting user trust rather than software vulnerabilities.
Rethinking Identity Defense
Defending against ConsentFix requires monitoring how users interact with web pages, not just where they log in from. Behavioral telemetry at the browser layer becomes critical.
Lessons for Security Teams
Relying solely on default cloud security configurations is no longer sufficient. Attackers actively study these defaults and design techniques to slip between them.
Why This Technique Will Spread
The effectiveness of ConsentFix, combined with its low technical complexity, makes it attractive to both red teams and adversaries. Once public, techniques rarely remain exclusive for long.
A Turning Point for OAuth Abuse
ConsentFix marks a shift from theoretical OAuth abuse to practical, scalable exploitation. It demonstrates that identity protocols themselves can be weaponized.
The Importance of Community Response
The rapid sharing of intelligence, detections, and mitigations helped contain the immediate threat. Without this collaboration, many organizations would still be unaware of the risk.
The Bigger Picture
ConsentFix is not just a single attack technique. It is a signal that identity security models must evolve alongside attacker creativity.
What Undercode Say: ConsentFix Changes the Rules
ConsentFix represents a fundamental escalation in identity-layer attacks. For years, defenders have invested heavily in MFA, passwordless authentication, and Conditional Access, believing these controls formed an almost impenetrable barrier. ConsentFix demonstrates that attackers no longer need to break authentication if they can simply step around it.
The most troubling aspect is not the technical novelty, but the trust abuse. Microsoft first-party apps are implicitly trusted by users and administrators alike. When attackers exploit this trust, detection becomes a human problem as much as a technical one. Users see a real Microsoft page, a real login flow, and no obvious red flags.
From a defensive standpoint, ConsentFix exposes how brittle OAuth visibility still is. Legacy scopes, incomplete logging, and pre-consented apps create blind spots that attackers clearly understand better than many organizations do. This is not a zero-day vulnerability; it is a zero-assumption failure.
The rapid emergence of improved variants also underscores how quickly attacker tooling evolves once a concept proves viable. Security teams cannot rely on static controls or point-in-time hardening. Continuous monitoring of browser behavior, consent flows, and anomalous authorization patterns is now essential.
ConsentFix should force a reassessment of what “phishing-resistant” really means. If authentication can be bypassed entirely, then resistance must extend beyond login events and into the full lifecycle of authorization and session use.
Ultimately, ConsentFix is less about OAuth itself and more about mindset. Attackers are no longer trying to steal keys; they are convincing users to hand them over willingly, wrapped in legitimate workflows. That shift demands a new defensive posture, one that treats the browser as a critical security boundary rather than a passive interface.
Fact Checker Results
✅ ConsentFix is a real OAuth-based attack technique observed in active campaigns.
✅ The attack can
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