AIX must enforce the limit of three consecutive invalid login attempts by a user before the user account is locked and released by an administrator.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-215171	SRG-OS-000021-GPOS-00005	AIX7-00-001003	SV-215171r958388_rule	2024-08-16	3

Description
By limiting the number of failed login attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128

ℹ️ Check
From the command prompt, execute the following command to check the system default value for the maximum number of tries before the system will lock the account: # lssec -f /etc/security/user -s default -a loginretries The above command should yield the following output: default loginretries=0 If the default value is "0" or greater than "3", this is a finding. From the command prompt, execute the following command to check all active accounts on the system for the maximum number of tries before the system will lock the account: # lsuser -a loginretries ALL \| more The above command should yield the following output: root loginretries=3 user1 loginretries=2 If a user has values set to "0" or greater than "3", this is a finding.

ℹ️ Check

From the command prompt, execute the following command to check the system default value for the maximum number of tries before the system will lock the account: # lssec -f /etc/security/user -s default -a loginretries The above command should yield the following output: default loginretries=0 If the default value is "0" or greater than "3", this is a finding. From the command prompt, execute the following command to check all active accounts on the system for the maximum number of tries before the system will lock the account: # lsuser -a loginretries ALL | more The above command should yield the following output: root loginretries=3 user1 loginretries=2 If a user has values set to "0" or greater than "3", this is a finding.

✔️ Fix
From the command prompt, execute the following command to configure the number of unsuccessful logins resulting in account lockout for "default:" stanza in "/etc/security/user" file: # chsec -f /etc/security/user -s default -a loginretries=3 From the command prompt, execute the following command to configure the number of unsuccessful logins resulting in account lockout for all users who have loginretries values that are 0 or greater than 3: # chsec -f /etc/security/user -s [user_name] -a loginretries=3

✔️ Fix

From the command prompt, execute the following command to configure the number of unsuccessful logins resulting in account lockout for "default:" stanza in "/etc/security/user" file: # chsec -f /etc/security/user -s default -a loginretries=3 From the command prompt, execute the following command to configure the number of unsuccessful logins resulting in account lockout for all users who have loginretries values that are 0 or greater than 3: # chsec -f /etc/security/user -s [user_name] -a loginretries=3