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Despite widespread adoption of multi-factor authentication (MFA) as a critical safeguard against unauthorized access, cybercriminals are once again one step ahead. According to a detailed report by Cisco Talos, threat actors are now bypassing MFA mechanisms using Adversary-in-the-Middle (AiTM) attacks—a tactic that exploits reverse proxies to intercept credentials and session cookies, enabling full account takeover.
“Cybercriminals are bypassing multi-factor authentication (MFA) using adversary-in-the-middle (AiTM) attacks via reverse proxies, intercepting credentials and authentication cookies,” the report explains.
The rise of Phishing-as-a-Service (PhaaS) toolkits allow even low-skill attackers to run campaigns with professional-level infrastructure.
Among the most dangerous:
- Tycoon 2FA
- Evilproxy
- Greatness
- Rockstar 2FA
- Mamba 2FA
“The developers behind Phishing-as-a-Service (PhaaS) kits like Tycoon 2FA and Evilproxy have added features to make them easier to use and harder to detect,” the report wanrs.
These platforms often feature:
- Pre-built phishing templates for popular services
- Link access control and geofencing
- Anti-bot and anti-crawler logic
- Delayed lure activation to avoid email scanners
- Obfuscated JavaScript injection for cookie harvesting
AiTM phishing campaigns follow a distinct pattern:
- Victim receives a phishing link (e.g., to a fake login page).
- That link connects to a reverse proxy server, not a clone.
- Victim enters credentials, which are relayed to the legitimate site.
- The MFA prompt is passed to the victim as normal.
- Upon approval, the authentication cookie is intercepted.
- Attacker uses this cookie to hijack the session—MFA already passed.
“The attacker now possesses both the victim’s username/password as well as an authentication cookie from the legitimate site,” the report explains.
Tools like Evilginx, originally built for red-team testing, are now fueling many of these attacks. Though open source and legitimate in intent, it has been repurposed by malicious actors.
Cisco Talos notes several indicators of Evilginx-powered attacks:
- New or suspicious TLS certificates from Let’s Encrypt
- Session cookies used simultaneously from different IPs
- URL path anomalies from servers not matching legitimate services
- TLS fingerprint mismatches between proxies and real domains
“Unless the attacker is careful, for a time, there will be two different users with different User-Agents and IP addresses using the same session cookie.”
The report highlights WebAuthn, a passwordless authentication method using public-key cryptography, as a robust defense against AiTM threats.
“WebAuthn is essentially passwordless… No passwords are ever entered into a web form, and no passwords are transmitted over the internet.”
WebAuthn protects users in two key ways:
- Origin binding: credentials are tied to specific domains, breaking proxy-based phishing chains.
- No password entry: removes the opportunity for interception entirely.
Unfortunately, adoption remains low despite its strength. Cisco Talos’ telemetry data suggests WebAuthn still accounts for a very small portion of all MFA traffic.
Cisco Talos urges organizations to rethink their authentication strategy in light of these evolving threats:
- Implement phishing-resistant MFA like WebAuthn or hardware tokens
- Audit logs for signs of MFA bypass (e.g., new MFA devices or session reuse anomalies)
- Educate users on verifying URLs and recognizing AiTM lures
- Monitor newly registered domains mimicking internal portals
Related Posts:
- Google Chrome and Mozilla Firefox will support the new password-free standard, WebAuthn
- Tycoon 2FA: The Evolving Threat Bypassing Multi-Factor Authentication
- ESET’s Discovery: Blackwood’s AitM Attacks and the NSPX30 Implant
- Phishing Campaign Bypasses MFA to Target Meta Business Accounts, Putting Millions at Risk
- CISA Warns of Credential Risks Tied to Oracle Cloud Breach
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