Check: UBTU-20-010072
Canonical Ubuntu 20.04 LTS STIG:
UBTU-20-010072
(in versions v1 r12 through v1 r2)
Title
The Ubuntu operating system must automatically lock an account until the locked account is released by an administrator when three unsuccessful logon attempts have been made. (Cat III impact)
Discussion
By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-forcing, is reduced. Limits are imposed by locking the account. Satisfies: SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005
Check Content
Verify that the Ubuntu operating system utilizes the "pam_faillock" module with the following command: $ grep faillock /etc/pam.d/common-auth auth [default=die] pam_faillock.so authfail auth sufficient pam_faillock.so authsucc If the pam_faillock.so module is not present in the "/etc/pam.d/common-auth" file, this is a finding. Verify the pam_faillock module is configured to use the following options: $ sudo egrep 'silent|audit|deny|fail_interval| unlock_time' /etc/security/faillock.conf audit silent deny = 3 fail_interval = 900 unlock_time = 0 If the "silent" keyword is missing or commented out, this is a finding. If the "audit" keyword is missing or commented out, this is a finding. If the "deny" keyword is missing, commented out, or set to a value greater than 3, this is a finding. If the "fail_interval" keyword is missing, commented out, or set to a value greater than 900, this is a finding. If the "unlock_time" keyword is missing, commented out, or not set to 0, this is a finding.
Fix Text
Configure the Ubuntu operating system to utilize the "pam_faillock" module. Edit the /etc/pam.d/common-auth file. Add the following lines below the "auth" definition for pam_unix.so: auth [default=die] pam_faillock.so authfail auth sufficient pam_faillock.so authsucc Configure the "pam_faillock" module to use the following options: Edit the /etc/security/faillock.conf file and add/update the following keywords and values: audit silent deny = 3 fail_interval = 900 unlock_time = 0
Additional Identifiers
Rule ID: SV-238235r853414_rule
Vulnerability ID: V-238235
Group Title: SRG-OS-000329-GPOS-00128
Expert Comments
CCIs
Number | Definition |
---|---|
CCI-000044 |
The information system enforces the organization-defined limit of consecutive invalid logon attempts by a user during the organization-defined time period. |
CCI-002238 |
The information system automatically locks the account or node for either an organization-defined time period, until the locked account or node is released by an administrator, or delays the next logon prompt according to the organization-defined delay algorithm when the maximum number of unsuccessful logon attempts is exceeded. |
Controls
Number | Title |
---|---|
AC-7 |
Unsuccessful Logon Attempts |