Title

SLEM 5 must generate audit records for all uses of the "unlink", "unlinkat", "rename", "renameat", and "rmdir" 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 made by all programs on the system. Therefore, it is very important to use syscall rules only when absolutely necessary, since these affect performance. The more rules, the bigger the performance hit. The performance can be helped, however, by combining syscalls into one rule whenever possible.

Check Content

Verify SLEM 5 generates an audit record for all uses of the "unlink", "unlinkat", "rename", "renameat", and "rmdir" system calls with the following command: > sudo auditctl -l | grep 'unlink\|rename\|rmdir' -a always,exit -F arch=b32 -S unlink,unlinkat,rename,renameat,rmdir -F auid>=1000 -F auid!=-1 -F key=perm_mod -a always,exit -F arch=b64 -S unlink,unlinkat,rename,renameat,rmdir -F auid>=1000 -F auid!=-1 -F key=perm_mod If both the "b32" and "b64" audit rules are not defined for the "unlink", "unlinkat", "rename", "renameat", and "rmdir" syscalls, this is a finding. Note: The "key=" value is arbitrary and can be different from the example output above.

Fix Text

Configure SLEM 5 to generate an audit record for all uses of the "unlink", "unlinkat", "rename", "renameat", and "rmdir" system calls. Add or modify the following lines in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F arch=b32 -S unlink,unlinkat,rename,renameat,rmdir -F auid>=1000 -F auid!=unset -k perm_mod -a always,exit -F arch=b64 -S unlink,unlinkat,rename,renameat,rmdir -F auid>=1000 -F auid!=unset -k perm_mod To reload the rules file, restart the audit daemon: > sudo systemctl restart auditd.service or issue the following command: > sudo augenrules --load

Additional Identifiers

Rule ID: SV-261461r996790_rule

Vulnerability ID: V-261461

Group Title: SRG-OS-000468-GPOS-00212

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