Title

Ubuntu OS must generate audit records for successful/unsuccessful uses of the chown, fchown, fchownat, and lchown system calls. (Cat II impact)

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. Satisfies: SRG-OS-000064-GPOS-00033, SRG-OS-000462-GPOS-00206

Check Content

Verify Ubuntu OS generates an audit record upon successful/unsuccessful attempts to use the "chown", "fchown", "fchownat", and "lchown" system calls by using the following command: $ sudo auditctl -l | grep chown -a always,exit -F arch=b32 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=-1 -F key=perm_chng -a always,exit -F arch=b64 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=-1 -F key=perm_chng If the command does not return audit rules for the "chown", "fchown", "fchownat", and "lchown" syscalls or the lines are commented out, this is a finding. Note: The "key=" value is arbitrary and can be different from the example output above.

Fix Text

Configure the audit system to generate an audit event for any successful/unsuccessful use of the "chown", "fchown", "fchownat", and "lchown" system calls. Add or modify the following lines in the "/etc/audit/rules.d/stig.rules": -a always,exit -F arch=b32 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -k perm_chng -a always,exit -F arch=b64 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -k perm_chng To reload the rules file, issue the following command: $ sudo augenrules --load Note: The "-k <keyname>" at the end of the line gives the rule a unique meaning to help during an audit investigation. The <keyname> does not need to match the example above.

Additional Identifiers

Rule ID: SV-275719r1148207_rule

Vulnerability ID: V-275719

Group Title: SRG-OS-000064-GPOS-00033

Expert Comments

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