Record Events that Modify User/Group Information
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Description
If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d, in order to capture events that modify
account changes:
-w /etc/group -p wa -k audit_rules_usergroup_modification
-w /etc/passwd -p wa -k audit_rules_usergroup_modification
-w /etc/gshadow -p wa -k audit_rules_usergroup_modification
-w /etc/shadow -p wa -k audit_rules_usergroup_modification
-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, in order to capture events that modify
account changes:
-w /etc/group -p wa -k audit_rules_usergroup_modification
-w /etc/passwd -p wa -k audit_rules_usergroup_modification
-w /etc/gshadow -p wa -k audit_rules_usergroup_modification
-w /etc/shadow -p wa -k audit_rules_usergroup_modification
-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
Rationale
In addition to auditing new user and group accounts, these watches
will alert the system administrator(s) to any modifications. Any unexpected
users, groups, or modifications should be investigated for legitimacy.
Shell script
The following script can be run on the host to remediate the issue.
#!/bin/bash
# Perform the remediation
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
<ns10:sub idref="xccdf_org.ssgproject.content_value_function_fix_audit_watch_rule" use="legacy"/>
fix_audit_watch_rule "auditctl" "/etc/group" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "augenrules" "/etc/group" "wa" "audit_rules_usergroup_modification"
<ns10:sub idref="xccdf_org.ssgproject.content_value_function_fix_audit_watch_rule" use="legacy"/>
fix_audit_watch_rule "auditctl" "/etc/passwd" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "augenrules" "/etc/passwd" "wa" "audit_rules_usergroup_modification"
<ns10:sub idref="xccdf_org.ssgproject.content_value_function_fix_audit_watch_rule" use="legacy"/>
fix_audit_watch_rule "auditctl" "/etc/gshadow" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "augenrules" "/etc/gshadow" "wa" "audit_rules_usergroup_modification"
<ns10:sub idref="xccdf_org.ssgproject.content_value_function_fix_audit_watch_rule" use="legacy"/>
fix_audit_watch_rule "auditctl" "/etc/shadow" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "augenrules" "/etc/shadow" "wa" "audit_rules_usergroup_modification"
<ns10:sub idref="xccdf_org.ssgproject.content_value_function_fix_audit_watch_rule" use="legacy"/>
fix_audit_watch_rule "auditctl" "/etc/security/opasswd" "wa" "audit_rules_usergroup_modification"
fix_audit_watch_rule "augenrules" "/etc/security/opasswd" "wa" "audit_rules_usergroup_modification"
Warning
This rule checks for multiple syscalls related to account changes;
it was written with DISA STIG in mind. Other policies should use a
separate rule for each syscall that needs to be checked. For example:
audit_rules_usergroup_modification_groupaudit_rules_usergroup_modification_gshadowaudit_rules_usergroup_modification_passwd
