diff --git a/lib/sub-process.ts b/lib/sub-process.ts
index bffcea5..368ef38 100644
--- a/lib/sub-process.ts
+++ b/lib/sub-process.ts
@@ -4,7 +4,7 @@ export function execute(command: string,
                         args: string[],
                         options?: { cwd?: string, env?: any },
                         shell: boolean = false): Promise<string> {
-  const spawnOptions: childProcess.SpawnOptions = { shell, env: process.env };
+  const spawnOptions: childProcess.SpawnOptions = { shell, env: {...process.env} };
   if (options?.cwd) {
     spawnOptions.cwd = options.cwd;
   }
diff --git a/test/sub-process.test.ts b/test/sub-process.test.ts
new file mode 100644
index 0000000..a75c14f
--- /dev/null
+++ b/test/sub-process.test.ts
@@ -0,0 +1,35 @@
+import { test } from 'tap';
+import { execute } from '../lib/sub-process';
+
+test('sub-process', (t) => {
+  let preTestEnv;
+  t.beforeEach(async () => {
+    preTestEnv = { ...process.env };
+  });
+
+  t.afterEach(async () => {
+    process.env = { ...preTestEnv };
+  });
+
+  t.test('restore proxy environment', async (t) => {   
+    process.env.SNYK_SYSTEM_HTTPS_PROXY = "http://1.1.1.1";
+    process.env.SNYK_SYSTEM_HTTP_PROXY = "http://2.2.2.2";
+    process.env.SNYK_SYSTEM_NO_PROXY = "snyk.com";
+    
+    process.env.HTTPS_PROXY = "http://127.0.0.1";
+    process.env.HTTP_PROXY = "http://127.0.0.1";
+    process.env.NO_PROXY = "example.com";
+
+    const result = await execute('env', []);
+
+    t.contains(result, 'HTTPS_PROXY=http://1.1.1.1');
+    t.contains(result, 'HTTP_PROXY=http://2.2.2.2');
+    t.contains(result, 'NO_PROXY=snyk.com');
+
+    t.equals(process.env.HTTPS_PROXY, 'http://127.0.0.1');
+    t.equals(process.env.HTTP_PROXY, 'http://127.0.0.1');
+    t.equals(process.env.NO_PROXY, 'example.com');
+  });
+
+  t.end();
+});