Audit objectives related to system maintenance
Detect unauthorized program maintenance determine that (1) maintenance procedures protect application form unauthorized changes (2) application are free from material errors, and (3) program libraries are protected from unauthorized access
We will examine each of these objectives in turn focusing on the tests of controls that are necessary to achieve the objective
Audit procedures related to system maintenance
Identify unauthorized changes to establish that program change were authorized the auditor should examine the audit trail of program changes for a sample of applications that have undergone maintenance
Reconcile program version numbers the permanent file of the application should contain program change authorization documents that correspond to the current version number of the production application in other words if the production application is in its tenth version there should be ten program change authorizations in the permanent file as supporting documentation any discrepancies between version numbers and supporting document may indicate that unauthorized changes were made
Confirm maintenance authorization the program maintenance authorization document should indicate the nature of the change requested and the data of the change it should also be signed and approved by the appropriate management from both computer services and the user departments the auditor should confirm the facts contained in the maintenance authorization and verify the authorizing signatures with the managers involved
Identify application Errors the auditor can determine that programs are free from material errors by performing three types of test o controls: reconciling the source code reviewing the test results and retesting the program
Reconcile the source code each application’s permanent file should contain the current program listing and listings of all changes made to the application these documents describe in detail the application’s maintenance history
Review test results every program change should be thoroughly tested before being implemented program test procedures should be properly documented by test objectives test data And processing results which support the programmer’s decision to implement the change the auditor should review this record for each significant program change to establish that testing was sufficiently rigorous to identify any errors
Retest the program the auditor can retest the application to confirm its integrity we examine several techniques for application testing in chapter 7
Test Access to libraries the existence of a secure program library is central to preventing errors and program fraud
The auditor should establish that the program library and private libraries are protected from unauthorized access by performing the following tests of controls
Review programmer authority tables the auditor can select a sample of programmers and review their access authority