The Oracle Linux operating system must audit all uses of the fchmod syscall.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-99305	OL07-00-030420	SV-108409r2_rule		Medium

Description
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). 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-000458-GPOS-00203, SRG-OS-000392-GPOS-00172, SRG-OS-000064-GPOS-00033

Description

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). 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-000458-GPOS-00203, SRG-OS-000392-GPOS-00172, SRG-OS-000064-GPOS-00033

STIG	Date
Oracle Linux 7 Security Technical Implementation Guide	2020-05-29

Details

Check Text ( C-98151r2_chk )
Verify the operating system generates audit records when successful/unsuccessful attempts to use the "fchmod" syscall occur. Check the file system rules in "/etc/audit/audit.rules" with the following command: Note: The output lines of the command are duplicated to cover both 32-bit and 64-bit architectures. Only the lines appropriate for the system architecture must be present. # grep -iw fchmod /etc/audit/audit.rules -a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -k perm_mod -a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -k perm_mod If there are no audit rules defined for the "fchmod" syscall, this is a finding.

Check Text ( C-98151r2_chk )

Verify the operating system generates audit records when successful/unsuccessful attempts to use the "fchmod" syscall occur.

Check the file system rules in "/etc/audit/audit.rules" with the following command:

Note: The output lines of the command are duplicated to cover both 32-bit and 64-bit architectures. Only the lines appropriate for the system architecture must be present.

# grep -iw fchmod /etc/audit/audit.rules

-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -k perm_mod

-a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -k perm_mod

If there are no audit rules defined for the "fchmod" syscall, this is a finding.

Fix Text (F-104987r2_fix)
Configure the operating system to generate audit records when successful/unsuccessful attempts to use the "fchmod" syscall occur. Add or update the following rule in "/etc/audit/rules.d/audit.rules": Note: The rules are duplicated to cover both 32-bit and 64-bit architectures. Only the lines appropriate for the system architecture must be configured. -a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -k perm_mod -a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -k perm_mod The audit daemon must be restarted for the changes to take effect.

Fix Text (F-104987r2_fix)

Configure the operating system to generate audit records when successful/unsuccessful attempts to use the "fchmod" syscall occur.

Add or update the following rule in "/etc/audit/rules.d/audit.rules":

Note: The rules are duplicated to cover both 32-bit and 64-bit architectures. Only the lines appropriate for the system architecture must be configured.

-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -k perm_mod

-a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -k perm_mod

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