3.7 - Understand Methods of Cryptanalytic Attacks CISSP Practice Questions (Page 1)

Questions 1–5

1. 1expert · hard

   A security team is evaluating the security of a cryptographic library used in a mobile app. The library is known to be cryptographically sound, but the team is concerned about attacks that target the implementation rather than the algorithm. Which type of attack should they focus on?

   • ABrute force attack, trying all possible keys
   • BCiphertext-only attack, using statistical analysis
   • CImplementation attacks, such as side-channel and timing attacks, that exploit flaws in how the algorithm is implemented
   • DKnown-plaintext attack, using known plaintext-ciphertext pairs
   Reveal Solution Discussion Select an answer first
2. 2foundation · easy

   Which attack exploits variations in the execution time of cryptographic operations?

   • ASide-channel attack
   • BTiming attack
   • CBrute force attack
   • DFault injection attack
   Reveal Solution Discussion Select an answer first
4. 3application · medium

   A company's file server has been infected with ransomware that encrypted all files and displayed a ransom note. The company has a backup strategy that includes daily snapshots. What is the most appropriate first response?

   • AAttempt to brute force the encryption key
   • BPay the ransom to obtain the decryption key
   • CRestore the files from the most recent clean backup
   • DDisconnect the server and ignore the incident
   Reveal Solution Discussion Select an answer first
5. 4expert · hard

   A security team is investigating a suspicious Kerberos ticket that was used to access a service. The ticket appears to have been forged using the service account's password hash. Which attack is indicated, and what is the most effective mitigation?

   • AKerberoasting; mitigate by using strong service account passwords
   • BGolden ticket attack; mitigate by resetting the KRBTGT password twice
   • CPass the hash attack; mitigate by enabling Credential Guard
   • DSilver ticket attack; mitigate by changing the service account password and monitoring for anomalous ticket usage
   Reveal Solution Discussion Select an answer first
6. 5application · medium

   During a forensic investigation, an analyst discovers an intercepted message that was encrypted with a classical substitution cipher. The analyst suspects the plaintext is English. Which technique would be most appropriate to begin deciphering the message?

   • AAttempt a brute force attack by trying every possible substitution key, which is computationally infeasible
   • BPerform frequency analysis on the ciphertext to map frequent symbols to common English letters
   • CApply a side-channel attack to measure the power consumption of the encryption device
   • DUse a chosen-plaintext attack by encrypting known phrases with the same cipher
   Reveal Solution Discussion Select an answer first