RHEL-08-030311 - Successful/unsuccessful uses of postdrop in RHEL 8 must generate an audit record.

Information

Reconstruction of harmful events or forensic analysis is not possible if audit records do not contain enough information.

At a minimum, the organization must audit the full-text recording of privileged commands. The organization must maintain audit trails in sufficient detail to reconstruct events to determine the cause and impact of compromise. The 'postdrop' command creates a file in the maildrop directory and copies its standard input to the file.

When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to '-1'. The AUID representation is an unsigned 32-bit integer, which equals '4294967295'. The audit system interprets '-1', '4294967295', and 'unset' in the same way.

Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Solution

Configure the audit system to generate an audit event for any successful/unsuccessful uses of the 'postdrop' by adding or updating the following rule in the '/etc/audit/rules.d/audit.rules' file:

-a always,exit -F path=/usr/sbin/postdrop -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update

The audit daemon must be restarted for the changes to take effect.

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_RHEL_8_V2R1_STIG.zip

Item Details

Category: AUDIT AND ACCOUNTABILITY

References: 800-53|AU-12a., CAT|II, CCI|CCI-000169, Rule-ID|SV-230427r1017228_rule, STIG-ID|RHEL-08-030311, Vuln-ID|V-230427

Plugin: Unix

Control ID: 3591e162f2e5a7f2f74b75e9c55da389070285b8aba65c58fecc1b479e831a7d