Legacy Auth

An old authentication daemon was discovered running on an internal server. The sysadmin claims it's been there "since the early 2000s" and refuses to update it.

Your mission: Bypass the authentication and retrieve the flag.

Binary Information:

Filename: legacy-auth
Size:     11,880 bytes (12 KB)
MD5:      fe519bc759768493d39624c257684d28
SHA1:     c1e092d2c6238606457dfc53303524e36567ca7e
SHA256:   6592bd0d2e5bd1ae63ad731727c90ce389205b78829f31296018f7bb8682c348

Verify integrity after download:

md5sum legacy-auth && sha1sum legacy-auth && sha256sum legacy-auth

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

Tip: Start by examining what functions exist in the binary...

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.