The auditor should select a sample of completed projects (completed in both the current period and previouse periods) and review documentation for evidence of compliance with SDLC policies specific points for review should include determining the following
User and computer services management properly authorized the project
A preliminary feasibility study showed that the project had merit
Test results show that the system was thoroughly tested at both the individual module and the total system level before implementation
Systems document documentation complies with organizational requirements and standards
The controlling system maintenance
The last two controllable activities pertain to system maintenance upon implementation the system enter the maintenance phase of the SDLC this is the longest period in the SDLC often spanning several years it is important to recognize that system do not remain static throughout this period rather they may undergo substantial changes that constitute a financial outlay many times their original cost if an application has undergone maintenance may have been compromised since implementation
In this section. We see how uncontrolled program changes can increase a firm’s exposure to financial misstatement due to programming errors some programming errors are subtle resulting in the creation and distribution of incorrect information that goesundetected by the user
Maintenance authorization testing and documentation
The benefits achieved from controlling new system development can be quickly lost during system maintenance if control does not continue into that phase. Access to systems for maintenance purposes increases the possibility of systems errors. Logic may be corrupted either by the accidental introduction of errors or intentional acts to defraud to minimum the potential exposure, all maintenance action should require as a minimum four controls: formal authorization technical specification of the changes retesting the system and updating the documentation
Source program library controls
In spite of the preceding maintenance procedures application integrity can be jeopardized by individuals who gain unauthorized access to programs the remainder of this section deals with control techniques and procedures for preventing and detecting unauthorized access to application programs.
In larger computer systems application program source code is stored on magnetic disks called the source program library figure 5.12 illustrates the relationship between the SPL and other key components of the operating environment
To execute a production application it must first be compiled and linked to create a load module that computer car process as a practical matter load modules are secure and free from the threat of unauthorized changes are accomplished by first making changes to the source code stored on the