The log entries clearly show an attacker attempting to access sensitive system files by manipulating the filename parameter. The use of ../../../ is a classic indicator of a directory traversal attack, also called path traversal. This technique is used to move outside the intended web directory and access restricted locations on the server’s filesystem.

In this case, the attacker is attempting to read:

/etc/passwd — contains user account information

/etc/shadow — contains hashed password entries and is even more sensitive

The CompTIA Security+ SY0-701 exam describes directory traversal as an attack where unvalidated user input allows navigation to system directories, often using sequences like ../ to bypass file path restrictions. This is exactly what is shown in the logs.

File injection (A) would involve inserting malicious files or code, not reading system files.

Privilege escalation (B) requires exploiting a system to gain higher privileges, not just reading files.

Cookie forgery (D) involves manipulating session cookies and does not match the observed behavior.

Because the attacker is using path traversal patterns to access protected files, the correct answer is C. Directory traversal.