The file integrity tool must notify the system administrator when changes to the baseline configuration or anomalies in the operation of any security functions are discovered.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-75523	UBTU-16-010540	SV-90203r3_rule		Medium

Description
Unauthorized changes to the baseline configuration could make the system vulnerable to various attacks or allow unauthorized access to the Ubuntu operating system. Changes to Ubuntu operating system configurations can have unintended side effects, some of which may be relevant to security. Security function is defined as the hardware, software, and/or firmware of the information system responsible for enforcing the system security policy and supporting the isolation of code and data on which the protection is based. Security functionality includes, but is not limited to, establishing system accounts, configuring access authorizations (i.e., permissions, privileges), setting events to be audited, and setting intrusion detection parameters. Detecting such changes and providing an automated response can help avoid unintended, negative consequences that could ultimately affect the security state of the Ubuntu operating system. The Ubuntu operating system's IMO/ISSO and SAs must be notified via email and/or monitoring system trap when there is an unauthorized modification of a configuration item. Notifications provided by information systems include messages to local computer consoles, and/or hardware indications, such as lights. This capability must take into account operational requirements for availability for selecting an appropriate response. The organization may choose to shut down or restart the information system upon security function anomaly detection. Satisfies: SRG-OS-000363-GPOS-00150, SRG-OS-000447-GPOS-00201

Description

Unauthorized changes to the baseline configuration could make the system vulnerable to various attacks or allow unauthorized access to the Ubuntu operating system. Changes to Ubuntu operating system configurations can have unintended side effects, some of which may be relevant to security. Security function is defined as the hardware, software, and/or firmware of the information system responsible for enforcing the system security policy and supporting the isolation of code and data on which the protection is based. Security functionality includes, but is not limited to, establishing system accounts, configuring access authorizations (i.e., permissions, privileges), setting events to be audited, and setting intrusion detection parameters. Detecting such changes and providing an automated response can help avoid unintended, negative consequences that could ultimately affect the security state of the Ubuntu operating system. The Ubuntu operating system's IMO/ISSO and SAs must be notified via email and/or monitoring system trap when there is an unauthorized modification of a configuration item. Notifications provided by information systems include messages to local computer consoles, and/or hardware indications, such as lights. This capability must take into account operational requirements for availability for selecting an appropriate response. The organization may choose to shut down or restart the information system upon security function anomaly detection. Satisfies: SRG-OS-000363-GPOS-00150, SRG-OS-000447-GPOS-00201

STIG	Date
Canonical Ubuntu 16.04 LTS Security Technical Implementation Guide	2018-07-18

Details

Check Text ( C-75227r3_chk )
Verify that Advanced Intrusion Detection Environment (AIDE) notifies the system administrator when anomalies in the operation of any security functions are discovered. Check that AIDE notifies the system administrator when anomalies in the operation of any security functions are discovered with the following command: # sudo grep SILENTREPORTS /etc/default/aide SILENTREPORTS=no If the "/etc/cron.daily/aide" file does not exist, the cron job is configured with the "SILENTREPORTS=yes" option, or the line is commented out, this is a finding.

Check Text ( C-75227r3_chk )

Verify that Advanced Intrusion Detection Environment (AIDE) notifies the system administrator when anomalies in the operation of any security functions are discovered.

Check that AIDE notifies the system administrator when anomalies in the operation of any security functions are discovered with the following command:

# sudo grep SILENTREPORTS /etc/default/aide

SILENTREPORTS=no

If the "/etc/cron.daily/aide" file does not exist, the cron job is configured with the "SILENTREPORTS=yes" option, or the line is commented out, this is a finding.

Fix Text (F-82151r2_fix)
Modify the "SILENTREPORTS" parameter in "/etc/default/aide" file with a value "no" of if it does not already exist: SILENTREPORTS=no