iso27diy-corp/Corpus/ISMS/Segregation of Duties in Auditing.md

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Source Published July 2, 2020 Retrieved July 13, 2022

  • Segregation of duties is a fundamental element of internal controls.
  • Principle: no one person or group of employees should be in a position to commit and conceal errors or fraud in their day-to-day jobs.
  • General concept: prevent one person from having access to assets as well as responsibility for maintaining the accountability of those assets.

In a perfect system, no one person should handle more than one type of the following functions:

  1. Authorization (giving approval for a transaction)
  2. Custody (care and maintenance of assets)
  3. Record keeping (administration)
  4. Reconciliation (making accounts consistent)

(COBIT 5 uses Verification instead of Reconciliation, see this note).

Different levels of SOD:

  • Individual: different people perform different duties, e.g. a manager authorizes an employee to make a payment.
  • Unit-level: different departments perform different duties, e.g. sales creates a project proposal, risk management approves it. 
  • Company-level: different entities perform operations, e.g. a holding company authorizes an investment of a subsidiary, or an accountancy firm performs a third-party audit.

Examples of internal control mechanisms for enforcing segregation of duties:

  • Audit trails, to recreate the transaction flow from origin to registration in an audit file. The audit trail should provide information on:
    • who initiated the transaction
    • date and timeof entry
    • type of entry
    • fields of information it contained
    • what files the transaction updated.
  • exception reports should be handled by supervisors
  • exceptions should be documented to prove proper and timely handling, the document should be signed by the author
  • Log should be kept or generated for all processed system commands or application transactions.
  • Independent reviews of reports and logs should be conducted.