diff --git a/src/main/java/org/opensearch/security/support/SecurityUtils.java b/src/main/java/org/opensearch/security/support/SecurityUtils.java
index edf0e06207..cfe0f3f271 100644
--- a/src/main/java/org/opensearch/security/support/SecurityUtils.java
+++ b/src/main/java/org/opensearch/security/support/SecurityUtils.java
@@ -46,9 +46,10 @@
 public final class SecurityUtils {
     
     protected final static Logger log = LogManager.getLogger(SecurityUtils.class);
-    private static final Pattern ENV_PATTERN = Pattern.compile("\\$\\{env\\.([\\w]+)((\\:\\-)?[\\w]*)\\}");
-    private static final Pattern ENVBC_PATTERN = Pattern.compile("\\$\\{envbc\\.([\\w]+)((\\:\\-)?[\\w]*)\\}");
-    private static final Pattern ENVBASE64_PATTERN = Pattern.compile("\\$\\{envbase64\\.([\\w]+)((\\:\\-)?[\\w]*)\\}");
+    private static final String ENV_PATTERN_SUFFIX = "\\.([\\w=():]+)((\\:\\-)?[\\w=():]*)\\}";
+    static final Pattern ENV_PATTERN = Pattern.compile("\\$\\{env" + ENV_PATTERN_SUFFIX);
+    static final Pattern ENVBC_PATTERN = Pattern.compile("\\$\\{envbc" + ENV_PATTERN_SUFFIX);
+    static final Pattern ENVBASE64_PATTERN = Pattern.compile("\\$\\{envbase64" + ENV_PATTERN_SUFFIX);
     public static Locale EN_Locale = forEN();
 
 
diff --git a/src/test/java/org/opensearch/security/support/SecurityUtilsTest.java b/src/test/java/org/opensearch/security/support/SecurityUtilsTest.java
new file mode 100644
index 0000000000..1ebc9f5161
--- /dev/null
+++ b/src/test/java/org/opensearch/security/support/SecurityUtilsTest.java
@@ -0,0 +1,70 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ *
+ * Modifications Copyright OpenSearch Contributors. See
+ * GitHub history for details.
+ */
+package org.opensearch.security.support;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.function.Predicate;
+
+import org.junit.Test;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.equalTo;
+import static org.opensearch.security.support.SecurityUtils.ENVBASE64_PATTERN;
+import static org.opensearch.security.support.SecurityUtils.ENVBC_PATTERN;
+import static org.opensearch.security.support.SecurityUtils.ENV_PATTERN;
+
+public class SecurityUtilsTest {
+
+    private final Collection<String> interestingEnvKeyNames = List.of(
+        "=ExitCode",
+        "=C:",
+        "ProgramFiles(x86)",
+        "INPUT_GRADLE-HOME-CACHE-CLEANUP"
+    );
+    private final Collection<String> namesFromThisRuntimeEnvironment = System.getenv().keySet();
+
+    @Test
+    public void checkInterestingNamesForEnvPattern() {
+        checkKeysWithPredicate(interestingEnvKeyNames, "env", ENV_PATTERN.asMatchPredicate());
+    }
+
+    @Test
+    public void checkRuntimeKeyNamesForEnvPattern() {
+        checkKeysWithPredicate(namesFromThisRuntimeEnvironment, "env", ENV_PATTERN.asMatchPredicate());
+    }
+
+    @Test
+    public void checkInterestingNamesForEnvbcPattern() {
+        checkKeysWithPredicate(interestingEnvKeyNames, "envbc", ENVBC_PATTERN.asMatchPredicate());
+    }
+
+    @Test
+    public void checkInterestingNamesForEnvBase64Pattern() {
+        checkKeysWithPredicate(interestingEnvKeyNames, "envbase64", ENVBASE64_PATTERN.asMatchPredicate());
+    }
+
+    private void checkKeysWithPredicate(Collection<String> keys, String predicateName, Predicate<String> predicate) {
+        keys.forEach(envKeyName -> {
+            final String prefixWithKeyName = "${" + predicateName + "." + envKeyName;
+
+            final String baseKeyName = prefixWithKeyName + "}";
+            assertThat("Testing " + envKeyName + ", " + baseKeyName,
+                predicate.test(baseKeyName),
+                equalTo(true));
+
+            final String baseKeyNameWithDefault = prefixWithKeyName + ":-tTt}";
+            assertThat("Testing " + envKeyName + " with defaultValue, " + baseKeyNameWithDefault,
+                predicate.test(baseKeyNameWithDefault),
+                equalTo(true));
+        });
+    }
+}