What type of vulnerability allows a binary to be replaced with a malicious one due to improper permissions?

• A. Weak network credentials.
• B. Insecure storage of passwords.
• C. File system permissions.
• D. Poorly configured firewall rules.

Answer: (C)

The situation hinges on who can modify executable files on the system. If file system permissions are lax, an attacker who can write to the location of a critical binary (or to a directory in the executable’s path) can replace the legitimate binary with a malicious one. When the system or a user runs that program, the malicious code executes with the same privileges, leading to compromise or privilege escalation. This is a classic file tampering scenario: improper permissions on binaries or their directories allow substitution of trusted executables.

Other options focus on credentials, secret storage, or network defenses, which don’t inherently permit swapping an executable on disk. To mitigate, enforce strict ownership and write permissions on binaries, use integrity checks or digital signatures, and consider application whitelisting to prevent unauthorized replacements.