Very Strong Protected

spbctf

Task: statically linked stripped x86-64 ELF with ptrace anti-debug, multi-layer custom bytecode VMs, a custom zero-K MD5 hash, and a self-deleting output file. Solution: NOP the ptrace jne check, run under qemu-user, and bind-mount a capture file over /tmp/flag.txt so the program's unlink() fails (EBUSY), recovering the 40-byte flag content.