Library Card

The city library's card reader accepts patron credentials. But something about the way it processes input feels off - and there are interesting books on the shelves if you know where to look.

Your mission: find what the library is really offering.

Binary Information:

Filename: library-card
Size:     16,112 bytes (16 KB)
MD5:      dbe43208f515502f7ff152f24c66fb44
SHA1:     037d46a7d47acb116335de908f1a63c62fee2602
SHA256:   d9e0738fa00d740cef5291f9f8e19d751e7784837fbe06249cb4cced719ee467

Verify integrity after download:

md5sum library-card && sha1sum library-card && sha256sum library-card

Environment:
- Architecture: x86_64 (64-bit)
- Stack protector: Disabled
- NX: Enabled
- PIE: Disabled
- RELRO: Partial
- Symbols: Not stripped
- ASLR: Enabled (system-level)

Tip: The binary includes a companion library file. You will need both.

Note: Download the binary and libc for local analysis. The binary reads flag.txt from the current directory - use a dummy flag for testing. The real flag can only be captured by exploiting the live instance on the lab.