Emoji Shellcoding: 🛠️, 🧌, and 🤯
Hadrien Barral demonstrates crafting fully functional executable shellcode consisting entirely of valid multi-byte UTF-8 emoji characters.
Summary
The Art of Constrained Shellcode Development
Exploit developers frequently encounter restrictive character filters (alphanumeric, ASCII, uppercase) that eliminate traditional byte sequences.
Deconstructing UTF-8 Encoding and Emoji Byte Spaces
Hadrien Barral explores the 4-byte UTF-8 encoding space used by modern emoji characters, mapping valid emoji bytes to x86 and ARM instruction opcodes.
Synthesizing Valid Instructions and Register Setup
Barral demonstrates assembling self-modifying decoder loops and setting up register arguments using only valid emoji sequences.
Implications for Deep Packet Inspection and Filter Evasion
The presentation illustrates how emoji-encoded payloads slip past text filters, chat sanitizers, and signature-based intrusion detection systems.
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