diff --git a/rules/002_domain_model/002_0009_no_default_value.rego b/rules/002_domain_model/002_0009_no_default_value.rego
new file mode 100644
index 0000000..ea79a29
--- /dev/null
+++ b/rules/002_domain_model/002_0009_no_default_value.rego
@@ -0,0 +1,48 @@
+# METADATA
+# scope: package
+# title: Do not use default values on attributes
+# description: Avoid default values because it introduces hidden logic that is hard to detect via "find changes".
+# authors:
+# - Rick Schreuder <rick.schreuder@valcon.com>
+# custom:
+#  category: Maintainability
+#  rulename: NoDefaultValue
+#  severity: LOW
+#  rulenumber: 002_0009
+#  remediation: Remove the attribute default value and set it explicitly in logic where needed.
+#  input: .*DomainModels\$DomainModel\.yaml
+
+package app.mendix.domain_model.no_default_value
+
+import rego.v1
+
+# Load custom rule annotations (severity, category, rule number).
+annotation := rego.metadata.chain()[1].annotations
+
+# The file is valid only if no rule violations are found.
+default allow := false
+allow if count(errors) == 0
+
+# A default value is considered "set" if it exists AND it is not the empty string.
+has_default_value(default_value) if {
+  default_value != null
+  default_value != ""
+}
+
+# Emit an error for each attribute that defines a DefaultValue.
+errors contains error_message if {
+
+  some entity in input.Entities
+  some attribute in entity.Attributes
+  has_default_value(attribute.Value.DefaultValue)
+
+  error_message := sprintf("[%v, %v, %v] %v.%v has a default value set",
+    [
+      annotation.custom.severity,
+      annotation.custom.category,
+      annotation.custom.rulenumber,
+      entity.Name,
+      attribute.Name
+    ]
+  )
+}
\ No newline at end of file
diff --git a/rules/002_domain_model/002_0009_no_default_value_test.yaml b/rules/002_domain_model/002_0009_no_default_value_test.yaml
new file mode 100644
index 0000000..148e366
--- /dev/null
+++ b/rules/002_domain_model/002_0009_no_default_value_test.yaml
@@ -0,0 +1,23 @@
+TestCases:
+- name: allow attributes with no default value or empty/null default value
+  allow: true
+  input:
+    Entities:
+      - Name: Entity1
+        Attributes:
+          - Name: Attr1
+          - Name: Attr2
+            Value:
+              DefaultValue: null
+          - Name: Attr3
+            Value:
+              DefaultValue: ""
+- name: deny attribute with a default value set
+  allow: false
+  input:
+    Entities:
+      - Name: Entity1
+        Attributes:
+          - Name: Attr1
+            Value:
+              DefaultValue: "0"
\ No newline at end of file
diff --git a/rules/006_security/006_0001_exposed_constants.rego b/rules/006_security/006_0001_exposed_constants.rego
new file mode 100644
index 0000000..f5f8ae8
--- /dev/null
+++ b/rules/006_security/006_0001_exposed_constants.rego
@@ -0,0 +1,69 @@
+# METADATA
+# scope: package
+# title: Exposed constants with sensitive data
+# description: Constants with potentially sensitive data should not be exposed to the client.
+# authors:
+# - Bart Zantingh <bart.zantingh@nl.abnamro.com>
+# custom:
+#  category: Security
+#  rulename: ExposedConstants
+#  severity: HIGH
+#  rulenumber: "006_0001"
+#  remediation: Set constant's 'Exposed to client' setting to false.
+#  input: "**/*$Constant.yaml"
+package app.mendix.constants.exposed_constants
+
+import rego.v1
+
+annotation := rego.metadata.chain()[1].annotations
+
+default allow := false
+
+allow if count(errors) == 0
+
+exposed := input.ExposedToClient
+
+errors contains error if {
+	exposed
+
+	name := input.Name
+
+	error := sprintf(
+		"[%v, %v, %v] Constant %v is exposed to the client",
+		[
+			"MEDIUM",
+			annotation.custom.category,
+			annotation.custom.rulenumber,
+			name,
+		],
+	)
+}
+
+errors contains error if {
+	contains_sensitive_data
+	exposed
+
+	name := input.Name
+
+	error := sprintf(
+		"[%v, %v, %v] Constant %v is exposed to the client, and seems to contain sensitive data",
+		[
+			annotation.custom.severity,
+			annotation.custom.category,
+			annotation.custom.rulenumber,
+			name,
+		],
+	)
+}
+
+sensitive_keywords := [
+	"id", "ident",
+	"username", "user_name", "user", "usr", "uname",
+	"secret", "scrt",
+	"password", "pwd", "passwrd",
+]
+
+contains_sensitive_data if {
+	some keyword in sensitive_keywords
+	contains(lower(input.Name), keyword)
+}
diff --git a/rules/006_security/006_0001_exposed_constants_test.yaml b/rules/006_security/006_0001_exposed_constants_test.yaml
new file mode 100644
index 0000000..598f8cc
--- /dev/null
+++ b/rules/006_security/006_0001_exposed_constants_test.yaml
@@ -0,0 +1,16 @@
+TestCases:
+- name: allow not exposed with sensitive name
+  allow: true
+  input:
+    ExposedToClient: false
+    Name: CST_TestConstant_password
+- name: allow not exposed without sensitive name
+  allow: true
+  input:
+    ExposedToClient: false
+    Name: CST_TestConstant
+- name: deny exposed with sensitive name
+  allow: false
+  input:
+    ExposedToClient: true
+    Name: CST_TestConstant_Id