Tim Yeh

AWS Taiwan / Security Solution Architect

Tim Yeh, working at AWS Taiwan as a Security Solution Architecture, and also a senior threat researcher motivated by interest, has more than ten years cyber security experience. Right now Mainly focuses on Cloud Security and threat intelligence. Also focus on APT research, and IoT research, including hardware and software reversing and hacking, malware campaign finding, incident response, penetration test, and MITRE red / blue team ATT&CK. He also gave talks in HITCON, CodeBlue, HITB, FIRST, BotConf, CloudSec, and iThome CYBERSEC.

SPEECH
4/17 (Thu.) 11:00 - 11:30 4F 4A Incident Response Forum
Hello your MFA is bypassed: A Deep Dive into Cloud IR and MFA Security - Lessons Learned from a Real AWS

A cloud security incident revealed that merely changing credentials and rebuilding instances after a breach was insufficient without proper Incident Response (IR). The attackers swiftly regained access through the original vulnerabilities. Only after discovering their database had been completely exfiltrated did the customer initiate a comprehensive IR, revealing backdoors planted across critical instances. How did this occur? What design principles could mitigate such risks? Furthermore, evidence of anomalous logins to privileged accounts with MFA was discovered - what strategies could enhance this security layer?

This session explores a cloud IR case study, demonstrating how to leverage logs and cloud-native security services to uncover attack patterns, reconstruct the attack timeline, and identify hidden backdoors. By examining the attacker's methodology, we'll understand the rationale behind cloud security best practices and how poor least-privilege design enabled persistent unauthorized access. We'll conclude by analyzing traces of compromised MFA on privileged accounts, common MFA bypass techniques, and propose a novel automation strategies which meat zero trust approach for strengthening your security posture.