DIR_AUDIT is a SAP Parameter attribute which is used to control Directory for security audit files information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
This parameter specifies the directory in which security audit files are
to be created. The file name for security audit files is specified using
the parameter FN_AUDIT.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.