V-275724

Discussion

Without generating audit records specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The system call rules are loaded into a matching engine that intercepts each syscall that all programs on the system makes. Therefore, it is very important to only use syscall rules when absolutely necessary since these affect performance. The more rules, the bigger the performance hit. The performance is helped, though, by combining syscalls into one rule whenever possible.

Check Content

Verify Ubuntu OS generates audit records for any successful/unsuccessful use of "unlink", "unlinkat", "rename", "renameat", and "rmdir" system calls by using the following command: 
  
     $ sudo auditctl -l | grep 'unlink\|rename\|rmdir'  
     -a always,exit -F arch=b64 -S unlink,unlinkat,rename,renameat,rmdir -F auid>=1000 -F auid!=-1 -F key=delete  
     -a always,exit -F arch=b32 -S unlink,unlinkat,rename,renameat,rmdir -F auid>=1000 -F auid!=-1 -F key=delete  
  
If the command does not return audit rules for the "unlink", "unlinkat", "rename", "renameat", and "rmdir" syscalls or the lines are commented out, this is a finding.  
  
Note: The "key" allows for specifying an arbitrary identifier, and the string after it does not need to match the example output above.