webmedium

BC

spbctf

Task: Calculator service using bc command with character filter blocking letters g-w and y-z. Solution: Used shell wildcards (/b??/ca? expands to /bin/cat) to bypass the filter and read the flag file.

$ ls tags/ techniques/
command_injection_filter_bypassshell_wildcard_expansionheredoc_escape

🔒

Permission denied (requires tier.pro)

Sign in to access full writeups

Create a free account with GitHub, then upgrade to Pro.

$ssh [email protected]