Dead Drop

A classified note system lets agents create, view, and delete secret messages. But the cleanup protocol has a flaw, and sometimes deleted messages are not truly gone.

Your mission: exploit the ghost in the machine.

Binary Information:

Filename: dead-drop
Size:     16,832 bytes (16 KB)
MD5:      c10700be834406f059680f4c801db08f
SHA1:     7af13a2a75a151a87f6f4f69d7952dd624b0eab0
SHA256:   98de7ce247444da142ee3706563f23451aa911ce8c8587a392c30a8d2e1afa54

Verify integrity after download:

md5sum dead-drop && sha1sum dead-drop && sha256sum dead-drop

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

Tip: The program manages objects in dynamic memory. What happens when you use something that no longer exists?

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.