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Successful/unsuccessful uses of the chmod, fchmod, and fchmodat system calls in RHEL 8 must generate an audit record.

Overview

Finding IDVersionRule IDIA ControlsSeverity
V-230456RHEL-08-030490SV-230456r1017253_ruleCCI-000169medium
Description
Without generating audit records that are 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 "chmod" system call changes the file mode bits of each given file according to mode, which can be either a symbolic representation of changes to make, or an octal number representing the bit pattern for the new mode bits. The "fchmod" system call is used to change permissions of a file. The "fchmodat" system call is used to change permissions of a file relative to a directory file descriptor. 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. 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. Performance can be helped, however, by combining syscalls into one rule whenever possible. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210
STIGDate
Red Hat Enterprise Linux 8 Security Technical Implementation Guide2025-05-14

Related Frameworks

1 mapping across 5 frameworks
SCF0 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (15) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

END-01Endpoint Device Management (EDM)
1.00
END-04Malicious Code Protection (Anti-Malware)
1.00
END-06Endpoint File Integrity Monitoring (FIM)
1.00
MON-01Continuous Monitoring
1.00
MON-01.1Intrusion Detection & Prevention Systems (IDS & IPS)
1.00
MON-01.3Inbound & Outbound Communications Traffic
1.00
MON-01.4System Generated Alerts
1.00
MON-01.7File Integrity Monitoring (FIM)
1.00
MON-01.8Security Event Monitoring
1.00
MON-03Content of Event Logs
1.00

+5 more (top 10 by confidence shown)

NIST 800-530 mappings

No source states a mapping between these directly.

Also reachable in 2 hops (57) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

AC-16Security and Privacy Attributes
1.00
AC-17(1)Monitoring and Control
1.00
AC-2(1)Automated System Account Management
1.00
AC-2(11)Usage Conditions
1.00
AC-2(3)Disable Accounts
1.00
AC-2(4)Automated Audit Actions
1.00
AC-3Access Enforcement
1.00
AC-3(3)Mandatory Access Control
1.00
AC-6(9)Log Use of Privileged Functions
1.00
AC-7Unsuccessful Logon Attempts
1.00

+47 more (top 10 by confidence shown)

NIST 800-1710 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (2) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

3.3.1
1.00
3.3.2
1.00
CCI1 mapping
CCI-000169
1.00
NIST CSF 2.00 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (4) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

DE.CM-01
1.00
DE.CM-03
1.00
DE.CM-09
1.00
PR.PS-04
1.00

Who does this work

12 NICE work roles and 9 EC-Council certifications.

This is an inference across published mappings, not a single claim by anyone. This check maps to a control, which maps to a Cybersecurity Framework outcome, which NIST assigns to the work roles below. EC-Council separately maps its certifications to those same roles.

A certification prepares someone for a role. It is not evidence that a holder is qualified, and neither NIST nor EC-Council has stated that any certification here addresses this check.

Work-role assignments published by NIST (NICE Framework Components 2.2.0 and the CSF 2.0 OLIR crosswalk). Certification mappings published by EC-Council.

Details

Check Text (C-230456r1017253_chk)

Verify RHEL 8 generates an audit record upon successful/unsuccessful attempts to use the "chmod", "fchmod", and "fchmodat" syscalls by using the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep chmod /etc/audit/audit.rules -a always,exit -F arch=b32 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -k perm_mod -a always,exit -F arch=b64 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -k perm_mod If the command does not return an audit rule for "chmod", "fchmod", and "fchmodat", or any of the lines returned are commented out, this is a finding.

Fix Text (F-33100r809310_fix)

Configure the audit system to generate an audit event for any successful/unsuccessful use of the "chmod", "fchmod", and "fchmodat" syscalls by adding or updating the following line to "/etc/audit/rules.d/audit.rules": -a always,exit -F arch=b32 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -k perm_mod -a always,exit -F arch=b64 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -k perm_mod The audit daemon must be restarted for the changes to take effect.