Security level 10
At security level 10, you have no security protection. Therefore, security level 10 is not recommended. Running your server at this security level is both a security and integrity risk as you do not have the protection of the higher security levels, 40 and 50, activated and being enforced.
Beginning in Version 4 Release 3, you cannot set your security level to 10. If your system is currently at level 10, your system will remain at level 10 when you install Version 4 Release 3. If you change the system level to some other value, you cannot change it back to level 10.
When a new user signs on, the system creates a user profile with the profile name equal to the user ID specified on the sign-on display. If the same user signs on later with a different user ID, a new user profile is created. IBM-supplied user profiles shows the default values that are used when the system automatically creates a user profile.
The system performs authority checking at all levels of security. Because all user profiles created at security level 10 are given *ALLOBJ special authority, users successfully pass almost every authority check and have access to all resources. If you want to test the effect of moving to a higher security level, you can remove *ALLOBJ special authority from user profiles and grant those profiles the authority to use specific resources. However, this does not give you any security protection. Anyone can sign on with a new user ID, and a new profile is created with *ALLOBJ special authority. You cannot prevent this at security level 10.