Introduced in the Solaris 2.6 release to allow the stack to be marked as non-executable. This helps make buffer-overflow attacks more difficult.
This variable exists on all systems running Solaris 2.6 or later, but it is only effective on sun4u, sun4m, and sun4d architectures.
0 (disabled), 1 (enabled)
Yes. Does not affect currently running processes—only those created after the value is set.
Should be enabled at all times unless applications are deliberately placing executable code on the stack without using mprotect(2) to make the stack executable.