Pam_Apparmor must be configured to allow system administrators to pass information to any other Ubuntu operating system administrator or user, change security attributes, and to confine all non-privileged users from executing functions to include disabling, circumventing, or altering implemented security safeguards/countermeasures.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-75535	UBTU-16-010600	SV-90215r2_rule		Medium

Description
Discretionary Access Control (DAC) is based on the notion that individual users are "owners" of objects and therefore have discretion over who should be authorized to access the object and in which mode (e.g., read or write). Ownership is usually acquired as a consequence of creating the object or via specified ownership assignment. DAC allows the owner to determine who will have access to objects they control. An example of DAC includes user-controlled file permissions. When discretionary access control policies are implemented, subjects are not constrained with regard to what actions they can take with information for which they have already been granted access. Thus, subjects that have been granted access to information are not prevented from passing (i.e., the subjects have the discretion to pass) the information to other subjects or objects. A subject that is constrained in its operation by Mandatory Access Control policies is still able to operate under the less rigorous constraints of this requirement. Thus, while Mandatory Access Control imposes constraints preventing a subject from passing information to another subject operating at a different sensitivity level, this requirement permits the subject to pass the information to any subject at the same sensitivity level. The policy is bounded by the information system boundary. Once the information is passed outside the control of the information system, additional means may be required to ensure the constraints remain in effect. While the older, more traditional definitions of discretionary access control require identity-based access control, that limitation is not required for this use of discretionary access control. Satisfies: SRG-OS-000312-GPOS-00122, SRG-OS-000312-GPOS-00123, SRG-OS-000312-GPOS-00124, SRG-OS-000324-GPOS-00125

Description

Discretionary Access Control (DAC) is based on the notion that individual users are "owners" of objects and therefore have discretion over who should be authorized to access the object and in which mode (e.g., read or write). Ownership is usually acquired as a consequence of creating the object or via specified ownership assignment. DAC allows the owner to determine who will have access to objects they control. An example of DAC includes user-controlled file permissions. When discretionary access control policies are implemented, subjects are not constrained with regard to what actions they can take with information for which they have already been granted access. Thus, subjects that have been granted access to information are not prevented from passing (i.e., the subjects have the discretion to pass) the information to other subjects or objects. A subject that is constrained in its operation by Mandatory Access Control policies is still able to operate under the less rigorous constraints of this requirement. Thus, while Mandatory Access Control imposes constraints preventing a subject from passing information to another subject operating at a different sensitivity level, this requirement permits the subject to pass the information to any subject at the same sensitivity level. The policy is bounded by the information system boundary. Once the information is passed outside the control of the information system, additional means may be required to ensure the constraints remain in effect. While the older, more traditional definitions of discretionary access control require identity-based access control, that limitation is not required for this use of discretionary access control. Satisfies: SRG-OS-000312-GPOS-00122, SRG-OS-000312-GPOS-00123, SRG-OS-000312-GPOS-00124, SRG-OS-000324-GPOS-00125

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

Details

Check Text ( C-75239r2_chk )
Verify the Ubuntu operating system is configured to allow system administrators to pass information to any other Ubuntu operating system administrator or user. Check that "Pam_Apparmor" is installed on the system with the following command: # sudo apt list libpam-apparmor libpam-apparmor/xenial-updates,now 2.10.95-0ubuntu2.7 amd64 [installed] If the "Pam_Apparmor" package is not installed, this is a finding. Check that Pam_Apparmor has properly configured profiles # sudo apparmor_status apparmor module is loaded. 13 profiles are loaded. 13 profiles are in enforce mode. /sbin/dhclient ... lxc-container-default-with-nesting 0 profiles are in complain mode. If all loaded profiles are not in "enforce" mode, or there are any profiles in "complain" mode, this is a finding.

Check Text ( C-75239r2_chk )

Verify the Ubuntu operating system is configured to allow system administrators to pass information to any other Ubuntu operating system administrator or user.

Check that "Pam_Apparmor" is installed on the system with the following command:

# sudo apt list libpam-apparmor

libpam-apparmor/xenial-updates,now 2.10.95-0ubuntu2.7 amd64 [installed]

If the "Pam_Apparmor" package is not installed, this is a finding.

Check that Pam_Apparmor has properly configured profiles

# sudo apparmor_status

apparmor module is loaded.
13 profiles are loaded.
13 profiles are in enforce mode.
/sbin/dhclient
...
lxc-container-default-with-nesting
0 profiles are in complain mode.

If all loaded profiles are not in "enforce" mode, or there are any profiles in "complain" mode, this is a finding.

Fix Text (F-82163r1_fix)
Configure the Ubuntu operating system to allow system administrators to pass information to any other Ubuntu operating system administrator or user. Install "Pam_Apparmor" (if it is not installed) with the following command: # sudo apt-get install libpam-apparmor Enable/Activate "Apparmor" (if it is not already active) with the following command: # sudo systemctl enable apparmor.service Start "Apparmor" with the following command: # sudo systemctl start apparmor.service Note: Pam_Apparmor must have properly configured profiles. All configurations will be based on the actual system setup and organization. See the "Pam_Apparmor" documentation for more information on configuring profiles.

Fix Text (F-82163r1_fix)

Configure the Ubuntu operating system to allow system administrators to pass information to any other Ubuntu operating system administrator or user.

Install "Pam_Apparmor" (if it is not installed) with the following command:

# sudo apt-get install libpam-apparmor

Enable/Activate "Apparmor" (if it is not already active) with the following command:

# sudo systemctl enable apparmor.service

Start "Apparmor" with the following command:

# sudo systemctl start apparmor.service

Note: Pam_Apparmor must have properly configured profiles. All configurations will be based on the actual system setup and organization. See the "Pam_Apparmor" documentation for more information on configuring profiles.