Secure Data Destruction

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• for hard disk drives (HDDs)
  • data wiping methods
    • overwriting with zeros
    • or multiple patterns
  • process can include a single pass of zeros or more complex patterns involving multiple passes to thwart attempts at data recovery
• For solid-state drives (SSDs)
  • overwriting methods are less effective due to
    • wear leveling
    • bad block management
  • use commands such as the ATA Secure Erase
    • designed to handle the specific challenges of SSD technology by
    • instructs drive’s firmware to internally sanitize all stored data
      • including within inaccessible marked-as-bad memory cells

Asset Disposal

 Asset disposal/decommissioning is the policies and procedures that govern the removal of devices and software from production networks, and their subsequent disposal through sale, donation, or as waste.

• focus on the secure and compliant handling of data and storage devices at the end of their lifecycle
• important concepts:
  • Sanitization
    • process of thoroughly and completely removing data from a storage medium so that file remnants cannot be recovered
    • uses specialized techniques to ensure that the data becomes irretrievable
      • e.g., data wiping, degaussing, or encryption
    • particularly important when repurposing or donating storage devices
  • Destruction
    • asset disposal technique that ensures that data remnants are rendered physically or electronically inaccessible and irrevocable
    • physical destruction methods:
      • shredding, crushing, or incinerating storage devices
    • electronic destruction methods:
      • overwriting data multiple times
      • or using degaussing techniques to eliminate magnetic fields on storage media
    • crucial step in the decommissioning process
  • Certification
    • the documentation and verification of the data sanitization or destruction process
    • often involves obtaining a certificate of destruction or sanitization from a reputable third-party provider
      • attests that the data has been securely removed or destroyed in accordance with industry standards and regulations
      • provides an impartial evaluation
    • benefits:
      • maintain compliance with data protection requirements
      • provides evidence of due diligence
      • reduces the risk of legal liabilities

Overwriting

• Files deleted from a magnetic-type hard disk are not fully erased
  • sectors containing the data are marked as available for writing
  • data they contain are only removed as new files are added
• standard Windows format tool will only remove references to files and mark all sectors as usable
• standard method of sanitizing an HDD is called overwriting
  • can be performed using:
    • the drive’s firmware tools
    • or a utility program
• most basic type of overwriting is called zero filling
  • sets each bit to zero
  • Single pass zero filling can leave patterns that can be read with specialist tools
  • more secure method is to:
    • overwrite the content with one pass of all zeros
    • then a pass of all ones
    • and then a third pass in a pseudorandom pattern
  • some federal agencies require more than three passes
• can take considerable time