1. Right Answer: D
Explanation: Destroying magnetic media is the only way to assure that confidential information cannot be recovered. Degaussing or demagnetizing is not sufficient to fully erase information from magnetic media. The purpose of defragmentation is to eliminate fragmentation in file systems and does not remove information. Erasing or deleting magnetic media does not remove the information; this method simply changes a file's indexing information.
2. Right Answer: B
Explanation: Software for centralized tracking and monitoring would allow a USB usage policy to be applied to each user based on changing business requirements, and would provide for monitoring and reporting exceptions to management. A policy requiring dismissal may result in increased employee attrition and business requirements would not be properly addressed. Disabling ports would be complex to manage and might not allow for new business needs. Searching of personnel for USB storage devices at the entrance to a facility is not a practical solution since these devices are small and could be easily hidden.
3. Right Answer: D
Explanation: The most effective method is physical destruction. Running a low-level data wipe utility may leave some residual data that could be recovered; erasing data directories and formatting hard drives are easily reversed, exposing all data on the drive to unauthorized individuals.
4. Right Answer: B
Explanation: Obtaining the hash of the message ensures integrity; signing the hash of the message with the sender's private key ensures the authenticity of the origin, and encrypting the resulting message with the receiver's public key ensures confidentiality. The other choices are incorrect.
5. Right Answer: D
Explanation: It is important for the IS auditor to determine if any credit card information is stored on the local point-of-sale (POS) system. Any such information, if stored, should be encrypted or protected by other means to avoid the possibility of unauthorized disclosure. Manually inputting sale invoices into the accounting application is an operational issue, if the POS system were to be interfaced with the financial accounting application, the overall efficiency could be improved. The nonavailability of optical scanners to read bar codes of the products and power outages are operational issues.