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GSEC · Question #304

GSEC Question #304: Real Exam Question with Answer & Explanation

The correct answer is D. One-way hash. File integrity monitoring relies on cryptographic one-way hashes to detect unauthorized changes because any modification to a file produces a completely different hash value.

Question

When file integrity checking is enabled, what feature is used to determine if a monitored file has been modified?

Options

  • Afile size
  • BLast modified dale
  • CFile change notifications in the Application Event Log
  • DOne-way hash

Explanation

File integrity monitoring relies on cryptographic one-way hashes to detect unauthorized changes because any modification to a file produces a completely different hash value.

Common mistakes.

  • A. File size only changes when bytes are added or removed; an attacker can modify file contents while preserving the original size, making this check insufficient.
  • B. Last modified date is a filesystem metadata attribute that can be trivially reset by an attacker using tools like 'touch', so it cannot reliably indicate whether content was altered.
  • C. Application Event Log file change notifications rely on the OS logging subsystem, which an attacker with sufficient privileges can clear or disable, and they do not provide a cryptographic proof of content integrity.

Concept tested. Cryptographic hashing for file integrity verification

Reference. https://csrc.nist.gov/publications/detail/sp/800-92/final

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