A digitally signed executable is a program file accompanied by a cryptographic signature from a publisher. When the signature verifies, it can help confirm the file has not changed since it was signed and identify the signer. It does not prove that the program is safe, nor does it validate other files shipped beside it.
This distinction matters in attacks that pair a legitimate signed application with a malicious companion file, such as a DLL the application loads from its own folder. The executable may pass a signature check while the untrusted library runs alongside it. Defenders should verify the whole software package, check publisher and file hashes, and investigate which libraries an application loads and where they come from. Developers can reduce risk by using secure DLL-loading practices and unambiguous search paths.