Hello. I am Taeyang Lee, a security researcher at Theori. You can find me via handle @5unkn0wn.
I specialize in reverse engineering, finding vulnerabilities from closed sources, and developing exploits. I also have experienced a lot of binary/mobile analysis and white box penetration testing.
And, I play CTF as The Duck.
I am currently focusing on my research on Android Bootloader security. I’ve found several vulnerabilities from the Android bootloader.
I am also interested in binary obfuscation and developing a deobfuscator. I’ve researched modern obfuscators such as Themida, VMProtect, and Android solutions.
| 2024 | 1st | ACSC CTF | 5unkn0wn | Asia International |
| 2024 | 1st | LINE CTF | The Duck | Japan |
| 2023 | 1st | DEF CON 31 | MMM | Las Vegas, US |
| 2023 | 1st | Google CTF | MMM | N/A |
| 2023 | 1st | Whitehat Contest | The Duck | Seoul, South Korea |
| 2023 | 1st | LINE CTF | The Duck | Japan |
| 2023 | 1st | Samsung SSTF | The Duck | Seoul, South Korea |
| 2023 | 2nd | Blackhat MEA | The Duck | Riyadh, Saudi Arabia |
| 2023 | 2nd | WACON | The Duck | Seoul, South Korea |
| 2023 | 2nd | Cyber Conflict Exercise | The Duck | Seoul, South Korea |
| 2023 | 3rd | CODEGATE General | The Duck | Seoul, South Korea |
| 2022 | 1st | DEF CON 30 | MMM | Las Vegas, US |
| 2022 | 1st | CODEGATE General | The Duck | Seoul, South Korea |
| 2022 | 1st | Cyber Conflict Exercise | The Duck | Seoul, South Korea |
| 2022 | 1st | Samsung SSTF | The Duck | South Korea |
| 2022 | 2nd | Whitehat Contest | Kang-Jinoh fc | South Korea |
| 2022 | 2nd | WACON | The Duck | Seoul, South Korea |
| 2021 | 1st | Whitehat Contest | Kang-Jinoh fc | South Korea |
| 2021 | 1st | Samsung SSTF | The Duck | South Korea |
| 2021 | 1st | LINE CTF | The Duck | Japan |
| 2021 | 3rd | Cyber Conflict Exercise | Dream Retriever | South Korea |
| 2020 | 1st | Samsung SSTF | The Duck | Seoul, South Korea |
| 2020 | 1st | Whitehat Grand Prix 06 | KingTigerPrawn | Vietnam |
| 2020 | 1st | Cyber Conflict Exercise | SpaceX Rocket | Seoul, South Korea |
| 2020 | 1st | Digital Forensic Challenge | noname | Seoul, South Korea |
| 2019 | 1st | Cyber Conflict Exercise | Yook-Hae-Gong | Busan, South Korea |
| 2019 | 1st | Digital Forensic Challenge | noname | Seoul, South Korea |
| 2018 | 2nd | Whitehat Grand Prix 04 | coconutCoffee | Hanoi, Vietnam |
| 2018 | 2nd | Digital Forensic Challenge | Foreng2 | Seoul, South Korea |
| 2018 | 2nd | Cyber Conflict Exercise | LeaveCat | Jeju, South Korea |
| 2017 | 3rd | CODEGATE Junior | 5unkn0wn | Seoul, South Korea |
| 2016 | 1st | Whitehat Contest Junior | HackCat | Seoul, South Korea |
| 2016 | 2nd | CODEGATE Junior | 5unkn0wn | Seoul, South Korea |