Talk Back

A debug echo service echoes back whatever you send. But it's echoing more than it should...

Your mission: Make the service reveal its secrets.

Binary Information:

Filename: talk-back
Size:     15,260 bytes (15 KB)
MD5:      3b3a6878e24a3d5f45b73fc3d6adb9c0
SHA1:     e99a6f4e02ce519b89b41cb8eada42d7ca0fcd58
SHA256:   98c6cd336ba81e2d1484180a1d3d2e2aaba1907d18fb227970ff7f142e223bde

Verify integrity after download:

md5sum talk-back && sha1sum talk-back && sha256sum talk-back

Environment:
- Architecture: x86 (32-bit)
- Stack protector: Disabled
- NX: Enabled
- PIE: Disabled
- Symbols: Not stripped

Hint: The service claims to echo your input, but some inputs produce unexpected output...

Note: Download the binary for local analysis. It 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.