diff --git a/.github/workflows/test-on-pr.yml b/.github/workflows/test-on-pr.yml
index 740d741..7b93768 100644
--- a/.github/workflows/test-on-pr.yml
+++ b/.github/workflows/test-on-pr.yml
@@ -46,7 +46,7 @@ jobs:
         include:
           # Common production setup
           - node_version: "20"
-            npm_version: "10.0.0"
+            npm_version: "10.2.0"
             yarn_version: "4.0.0"
             pnpm_version: "9.0.0"
           # Current Active LTS with latest tools
@@ -66,7 +66,7 @@ jobs:
             pnpm_version: "latest"
           # Version pinning scenario
           - node_version: "22"
-            npm_version: "10.0.0"
+            npm_version: "10.2.0"
             yarn_version: "4.0.0"
             pnpm_version: "9.0.0"
           # Backward compatibility testing
@@ -82,7 +82,7 @@ jobs:
           # EOL compatibility testing - Node 16 (EOL Sept 2023)
           - node_version: "16"
             npm_version: "8.0.0"
-            yarn_version: "3.6.0"
+            yarn_version: "1.22.0"
             pnpm_version: "8.0.0"
 
     steps:
diff --git a/package-lock.json b/package-lock.json
index 4840448..6b74d53 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -3323,6 +3323,15 @@
         "node": ">= 0.6"
       }
     },
+    "node_modules/node-forge": {
+      "version": "1.3.1",
+      "resolved": "https://registry.npmjs.org/node-forge/-/node-forge-1.3.1.tgz",
+      "integrity": "sha512-dPEtOeMvF9VMcYV/1Wb8CPoVAXtp6MKMlcbAt4ddqmGqUJ6fQZFXkNZNkNlfevtNkGtaSoXf/vNNNSvgrdXwtA==",
+      "license": "(BSD-3-Clause OR GPL-2.0)",
+      "engines": {
+        "node": ">= 6.13.0"
+      }
+    },
     "node_modules/node-pty": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/node-pty/-/node-pty-1.0.0.tgz",
@@ -4877,7 +4886,9 @@
       "dependencies": {
         "abbrev": "3.0.1",
         "chalk": "5.4.1",
+        "https-proxy-agent": "7.0.6",
         "make-fetch-happen": "14.0.3",
+        "node-forge": "1.3.1",
         "npm-registry-fetch": "18.0.2",
         "ora": "8.2.0",
         "semver": "7.7.2"
diff --git a/packages/safe-chain/bin/aikido-npm.js b/packages/safe-chain/bin/aikido-npm.js
index 4176db1..d8b8c3e 100755
--- a/packages/safe-chain/bin/aikido-npm.js
+++ b/packages/safe-chain/bin/aikido-npm.js
@@ -6,7 +6,9 @@ import { initializePackageManager } from "../src/packagemanager/currentPackageMa
 
 const packageManagerName = "npm";
 initializePackageManager(packageManagerName, getNpmVersion());
-await main(process.argv.slice(2));
+var exitCode = await main(process.argv.slice(2));
+
+process.exit(exitCode);
 
 function getNpmVersion() {
   try {
diff --git a/packages/safe-chain/bin/aikido-npx.js b/packages/safe-chain/bin/aikido-npx.js
index 067608c..7f06c7c 100755
--- a/packages/safe-chain/bin/aikido-npx.js
+++ b/packages/safe-chain/bin/aikido-npx.js
@@ -5,4 +5,6 @@ import { initializePackageManager } from "../src/packagemanager/currentPackageMa
 
 const packageManagerName = "npx";
 initializePackageManager(packageManagerName, process.versions.node);
-await main(process.argv.slice(2));
+var exitCode = await main(process.argv.slice(2));
+
+process.exit(exitCode);
diff --git a/packages/safe-chain/bin/aikido-pnpm.js b/packages/safe-chain/bin/aikido-pnpm.js
index e7bac47..7177159 100755
--- a/packages/safe-chain/bin/aikido-pnpm.js
+++ b/packages/safe-chain/bin/aikido-pnpm.js
@@ -5,4 +5,6 @@ import { initializePackageManager } from "../src/packagemanager/currentPackageMa
 
 const packageManagerName = "pnpm";
 initializePackageManager(packageManagerName, process.versions.node);
-await main(process.argv.slice(2));
+var exitCode = await main(process.argv.slice(2));
+
+process.exit(exitCode);
diff --git a/packages/safe-chain/bin/aikido-pnpx.js b/packages/safe-chain/bin/aikido-pnpx.js
index 25884ce..4bb6840 100755
--- a/packages/safe-chain/bin/aikido-pnpx.js
+++ b/packages/safe-chain/bin/aikido-pnpx.js
@@ -5,4 +5,6 @@ import { initializePackageManager } from "../src/packagemanager/currentPackageMa
 
 const packageManagerName = "pnpx";
 initializePackageManager(packageManagerName, process.versions.node);
-await main(process.argv.slice(2));
+var exitCode = await main(process.argv.slice(2));
+
+process.exit(exitCode);
diff --git a/packages/safe-chain/bin/aikido-yarn.js b/packages/safe-chain/bin/aikido-yarn.js
index a0eaaf6..002a956 100755
--- a/packages/safe-chain/bin/aikido-yarn.js
+++ b/packages/safe-chain/bin/aikido-yarn.js
@@ -5,4 +5,6 @@ import { initializePackageManager } from "../src/packagemanager/currentPackageMa
 
 const packageManagerName = "yarn";
 initializePackageManager(packageManagerName, process.versions.node);
-await main(process.argv.slice(2));
+var exitCode = await main(process.argv.slice(2));
+
+process.exit(exitCode);
diff --git a/packages/safe-chain/package.json b/packages/safe-chain/package.json
index 32228e7..d28fe73 100644
--- a/packages/safe-chain/package.json
+++ b/packages/safe-chain/package.json
@@ -30,7 +30,9 @@
   "dependencies": {
     "abbrev": "3.0.1",
     "chalk": "5.4.1",
+    "https-proxy-agent": "7.0.6",
     "make-fetch-happen": "14.0.3",
+    "node-forge": "1.3.1",
     "npm-registry-fetch": "18.0.2",
     "ora": "8.2.0",
     "semver": "7.7.2"
diff --git a/packages/safe-chain/src/main.js b/packages/safe-chain/src/main.js
index 81b1b3a..e106e83 100644
--- a/packages/safe-chain/src/main.js
+++ b/packages/safe-chain/src/main.js
@@ -4,20 +4,50 @@ import { scanCommand, shouldScanCommand } from "./scanning/index.js";
 import { ui } from "./environment/userInteraction.js";
 import { getPackageManager } from "./packagemanager/currentPackageManager.js";
 import { initializeCliArguments } from "./config/cliArguments.js";
+import { createSafeChainProxy } from "./registryProxy/registryProxy.js";
+import chalk from "chalk";
 
 export async function main(args) {
+  const proxy = createSafeChainProxy();
+  await proxy.startServer();
+
   try {
     // This parses all the --safe-chain arguments and removes them from the args array
     args = initializeCliArguments(args);
 
     if (shouldScanCommand(args)) {
-      await scanCommand(args);
+      const commandScanResult = await scanCommand(args);
+
+      // Returning the exit code back to the caller allows the promise
+      //  to be awaited in the bin files and return the correct exit code
+      if (commandScanResult !== 0) {
+        return commandScanResult;
+      }
     }
+
+    const packageManagerResult = await getPackageManager().runCommand(args);
+
+    if (!proxy.verifyNoMaliciousPackages()) {
+      return 1;
+    }
+
+    ui.emptyLine();
+    ui.writeInformation(
+      `${chalk.green(
+        "✔"
+      )} Safe-chain: Command completed, no malicious packages found.`
+    );
+
+    // Returning the exit code back to the caller allows the promise
+    //  to be awaited in the bin files and return the correct exit code
+    return packageManagerResult.status;
   } catch (error) {
     ui.writeError("Failed to check for malicious packages:", error.message);
-    process.exit(1);
-  }
 
-  var result = getPackageManager().runCommand(args);
-  process.exit(result.status);
+    // Returning the exit code back to the caller allows the promise
+    //  to be awaited in the bin files and return the correct exit code
+    return 1;
+  } finally {
+    await proxy.stopServer();
+  }
 }
diff --git a/packages/safe-chain/src/packagemanager/npm/dependencyScanner/dryRunScanner.js b/packages/safe-chain/src/packagemanager/npm/dependencyScanner/dryRunScanner.js
index 0db23cb..6189b2f 100644
--- a/packages/safe-chain/src/packagemanager/npm/dependencyScanner/dryRunScanner.js
+++ b/packages/safe-chain/src/packagemanager/npm/dependencyScanner/dryRunScanner.js
@@ -8,6 +8,7 @@ export function dryRunScanner(scannerOptions) {
     shouldScan: (args) => shouldScanDependencies(scannerOptions, args),
   };
 }
+
 function scanDependencies(scannerOptions, args) {
   let dryRunArgs = args;
 
@@ -31,8 +32,8 @@ function shouldScanDependencies(scannerOptions, args) {
   return true;
 }
 
-function checkChangesWithDryRun(args) {
-  const dryRunOutput = dryRunNpmCommandAndOutput(args);
+async function checkChangesWithDryRun(args) {
+  const dryRunOutput = await dryRunNpmCommandAndOutput(args);
 
   // Dry-run can return a non-zero status code in some cases
   //  e.g., when running "npm audit fix --dry-run", it returns exit code 1
diff --git a/packages/safe-chain/src/packagemanager/npm/dependencyScanner/dryRunScanner.spec.js b/packages/safe-chain/src/packagemanager/npm/dependencyScanner/dryRunScanner.spec.js
index 4fb6272..88d7681 100644
--- a/packages/safe-chain/src/packagemanager/npm/dependencyScanner/dryRunScanner.spec.js
+++ b/packages/safe-chain/src/packagemanager/npm/dependencyScanner/dryRunScanner.spec.js
@@ -36,7 +36,7 @@ describe("dryRunScanner", async () => {
       }));
 
       const scanner = dryRunScanner();
-      const result = scanner.scan(["audit", "fix"]);
+      const result = await scanner.scan(["audit", "fix"]);
 
       // Should not throw an error for audit fix commands
       assert.ok(Array.isArray(result));
@@ -53,8 +53,8 @@ describe("dryRunScanner", async () => {
 
       const scanner = dryRunScanner();
 
-      assert.throws(() => {
-        scanner.scan(["install", "lodash"]);
+      await assert.rejects(async () => {
+        await scanner.scan(["install", "lodash"]);
       }, /Dry-run command failed with exit code 1/);
     });
 
@@ -67,7 +67,7 @@ describe("dryRunScanner", async () => {
       }));
 
       const scanner = dryRunScanner();
-      const result = scanner.scan(["install", "lodash"]);
+      const result = await scanner.scan(["install", "lodash"]);
 
       assert.ok(Array.isArray(result));
       assert.equal(mockWriteError.mock.callCount(), 0);
@@ -83,8 +83,8 @@ describe("dryRunScanner", async () => {
 
       const scanner = dryRunScanner();
 
-      assert.throws(() => {
-        scanner.scan(["audit", "fix"]);
+      await assert.rejects(async () => {
+        await scanner.scan(["audit", "fix"]);
       }, /Dry-run command failed with exit code 1/);
     });
   });
@@ -99,7 +99,7 @@ describe("dryRunScanner", async () => {
       }));
 
       const scanner = dryRunScanner({ dryRunCommand: "install" });
-      scanner.scan(["install-test", "lodash"]);
+      await scanner.scan(["install-test", "lodash"]);
 
       // Should call with "install" instead of "install-test"
       assert.equal(mockDryRunNpmCommandAndOutput.mock.callCount(), 1);
diff --git a/packages/safe-chain/src/packagemanager/npm/runNpmCommand.js b/packages/safe-chain/src/packagemanager/npm/runNpmCommand.js
index 70a0d17..26a4a9d 100644
--- a/packages/safe-chain/src/packagemanager/npm/runNpmCommand.js
+++ b/packages/safe-chain/src/packagemanager/npm/runNpmCommand.js
@@ -1,10 +1,14 @@
-import { execSync } from "child_process";
 import { ui } from "../../environment/userInteraction.js";
+import { safeSpawn } from "../../utils/safeSpawn.js";
+import { mergeSafeChainProxyEnvironmentVariables } from "../../registryProxy/registryProxy.js";
 
-export function runNpm(args) {
+export async function runNpm(args) {
   try {
-    const npmCommand = `npm ${args.join(" ")}`;
-    execSync(npmCommand, { stdio: "inherit" });
+    const result = await safeSpawn("npm", args, {
+      stdio: "inherit",
+      env: mergeSafeChainProxyEnvironmentVariables(process.env),
+    });
+    return { status: result.status };
   } catch (error) {
     if (error.status) {
       return { status: error.status };
@@ -13,17 +17,29 @@ export function runNpm(args) {
       return { status: 1 };
     }
   }
-  return { status: 0 };
 }
 
-export function dryRunNpmCommandAndOutput(args) {
+export async function dryRunNpmCommandAndOutput(args) {
   try {
-    const npmCommand = `npm ${args.join(" ")} --ignore-scripts --dry-run`;
-    const output = execSync(npmCommand, { stdio: "pipe" });
-    return { status: 0, output: output.toString() };
+    const result = await safeSpawn(
+      "npm",
+      [...args, "--ignore-scripts", "--dry-run"],
+      {
+        stdio: "pipe",
+        env: mergeSafeChainProxyEnvironmentVariables(process.env),
+      }
+    );
+    return {
+      status: result.status,
+      output: result.status === 0 ? result.stdout : result.stderr,
+    };
   } catch (error) {
     if (error.status) {
-      const output = error.stdout ? error.stdout.toString() : "";
+      const output =
+        error.stdout?.toString() ??
+        error.stderr?.toString() ??
+        error.message ??
+        "";
       return { status: error.status, output };
     } else {
       ui.writeError("Error executing command:", error.message);
diff --git a/packages/safe-chain/src/packagemanager/npx/runNpxCommand.js b/packages/safe-chain/src/packagemanager/npx/runNpxCommand.js
index cc78abb..b8896b7 100644
--- a/packages/safe-chain/src/packagemanager/npx/runNpxCommand.js
+++ b/packages/safe-chain/src/packagemanager/npx/runNpxCommand.js
@@ -1,10 +1,14 @@
-import { execSync } from "child_process";
 import { ui } from "../../environment/userInteraction.js";
+import { safeSpawn } from "../../utils/safeSpawn.js";
+import { mergeSafeChainProxyEnvironmentVariables } from "../../registryProxy/registryProxy.js";
 
-export function runNpx(args) {
+export async function runNpx(args) {
   try {
-    const npxCommand = `npx ${args.join(" ")}`;
-    execSync(npxCommand, { stdio: "inherit" });
+    const result = await safeSpawn("npx", args, {
+      stdio: "inherit",
+      env: mergeSafeChainProxyEnvironmentVariables(process.env),
+    });
+    return { status: result.status };
   } catch (error) {
     if (error.status) {
       return { status: error.status };
@@ -13,5 +17,4 @@ export function runNpx(args) {
       return { status: 1 };
     }
   }
-  return { status: 0 };
 }
diff --git a/packages/safe-chain/src/packagemanager/pnpm/runPnpmCommand.js b/packages/safe-chain/src/packagemanager/pnpm/runPnpmCommand.js
index 0d5133f..794d6e3 100644
--- a/packages/safe-chain/src/packagemanager/pnpm/runPnpmCommand.js
+++ b/packages/safe-chain/src/packagemanager/pnpm/runPnpmCommand.js
@@ -1,13 +1,20 @@
 import { ui } from "../../environment/userInteraction.js";
-import { safeSpawnSync } from "../../utils/safeSpawn.js";
+import { mergeSafeChainProxyEnvironmentVariables } from "../../registryProxy/registryProxy.js";
+import { safeSpawn } from "../../utils/safeSpawn.js";
 
-export function runPnpmCommand(args, toolName = "pnpm") {
+export async function runPnpmCommand(args, toolName = "pnpm") {
   try {
     let result;
     if (toolName === "pnpm") {
-      result = safeSpawnSync("pnpm", args, { stdio: "inherit" });
+      result = await safeSpawn("pnpm", args, {
+        stdio: "inherit",
+        env: mergeSafeChainProxyEnvironmentVariables(process.env),
+      });
     } else if (toolName === "pnpx") {
-      result = safeSpawnSync("pnpx", args, { stdio: "inherit" });
+      result = await safeSpawn("pnpx", args, {
+        stdio: "inherit",
+        env: mergeSafeChainProxyEnvironmentVariables(process.env),
+      });
     } else {
       throw new Error(`Unsupported tool name for aikido-pnpm: ${toolName}`);
     }
diff --git a/packages/safe-chain/src/packagemanager/yarn/runYarnCommand.js b/packages/safe-chain/src/packagemanager/yarn/runYarnCommand.js
index c89c804..2c3795c 100644
--- a/packages/safe-chain/src/packagemanager/yarn/runYarnCommand.js
+++ b/packages/safe-chain/src/packagemanager/yarn/runYarnCommand.js
@@ -1,10 +1,17 @@
-import { execSync } from "child_process";
 import { ui } from "../../environment/userInteraction.js";
+import { safeSpawn } from "../../utils/safeSpawn.js";
+import { mergeSafeChainProxyEnvironmentVariables } from "../../registryProxy/registryProxy.js";
 
-export function runYarnCommand(args) {
+export async function runYarnCommand(args) {
   try {
-    const npxCommand = `yarn ${args.join(" ")}`;
-    execSync(npxCommand, { stdio: "inherit" });
+    const env = mergeSafeChainProxyEnvironmentVariables(process.env);
+    await fixYarnProxyEnvironmentVariables(env);
+
+    const result = await safeSpawn("yarn", args, {
+      stdio: "inherit",
+      env,
+    });
+    return { status: result.status };
   } catch (error) {
     if (error.status) {
       return { status: error.status };
@@ -13,5 +20,34 @@ export function runYarnCommand(args) {
       return { status: 1 };
     }
   }
-  return { status: 0 };
+}
+
+async function fixYarnProxyEnvironmentVariables(env) {
+  // Yarn ignores standard proxy environment variables HTTPS_PROXY and NODE_EXTRA_CA_CERTS
+
+  // Yarn v2/v3 and v4+ use different environment variables for proxy and CA certs
+  // When setting all variables, yarn returns an error about conflicting variables
+  //  - v2/v3: "Usage Error: Unrecognized or legacy configuration settings found: httpsCaFilePath"
+  //  - v4+:   "Usage Error: Unrecognized or legacy configuration settings found: caFilePath"
+
+  const version = await yarnVersion();
+  const majorVersion = parseInt(version.split(".")[0]);
+
+  if (majorVersion >= 4) {
+    env.YARN_HTTPS_PROXY = env.HTTPS_PROXY;
+    env.YARN_HTTPS_CA_FILE_PATH = env.NODE_EXTRA_CA_CERTS;
+  } else if (majorVersion === 2 || majorVersion === 3) {
+    env.YARN_HTTPS_PROXY = env.HTTPS_PROXY;
+    env.YARN_CA_FILE_PATH = env.NODE_EXTRA_CA_CERTS;
+  }
+}
+
+async function yarnVersion() {
+  const result = await safeSpawn("yarn", ["--version"], {
+    stdio: "pipe",
+  });
+  if (result.status !== 0) {
+    throw new Error("Failed to get yarn version");
+  }
+  return result.stdout.trim();
 }
diff --git a/packages/safe-chain/src/registryProxy/certUtils.js b/packages/safe-chain/src/registryProxy/certUtils.js
new file mode 100644
index 0000000..d5d414c
--- /dev/null
+++ b/packages/safe-chain/src/registryProxy/certUtils.js
@@ -0,0 +1,114 @@
+import forge from "node-forge";
+import path from "path";
+import fs from "fs";
+import os from "os";
+
+const certFolder = path.join(os.homedir(), ".safe-chain", "certs");
+const ca = loadCa();
+
+const certCache = new Map();
+
+export function getCaCertPath() {
+  return path.join(certFolder, "ca-cert.pem");
+}
+
+export function generateCertForHost(hostname) {
+  let existingCert = certCache.get(hostname);
+  if (existingCert) {
+    return existingCert;
+  }
+
+  const keys = forge.pki.rsa.generateKeyPair(2048);
+  const cert = forge.pki.createCertificate();
+  cert.publicKey = keys.publicKey;
+  cert.serialNumber = "01";
+  cert.validity.notBefore = new Date();
+  cert.validity.notAfter = new Date();
+  cert.validity.notAfter.setHours(cert.validity.notBefore.getHours() + 1);
+
+  const attrs = [{ name: "commonName", value: hostname }];
+  cert.setSubject(attrs);
+  cert.setIssuer(ca.certificate.subject.attributes);
+  cert.setExtensions([
+    {
+      name: "subjectAltName",
+      altNames: [
+        {
+          type: 2, // DNS
+          value: hostname,
+        },
+      ],
+    },
+    {
+      name: "keyUsage",
+      digitalSignature: true,
+      keyEncipherment: true,
+    },
+  ]);
+  cert.sign(ca.privateKey, forge.md.sha256.create());
+
+  const result = {
+    privateKey: forge.pki.privateKeyToPem(keys.privateKey),
+    certificate: forge.pki.certificateToPem(cert),
+  };
+
+  certCache.set(hostname, result);
+
+  return result;
+}
+
+function loadCa() {
+  const keyPath = path.join(certFolder, "ca-key.pem");
+  const certPath = path.join(certFolder, "ca-cert.pem");
+
+  if (fs.existsSync(keyPath) && fs.existsSync(certPath)) {
+    const privateKeyPem = fs.readFileSync(keyPath, "utf8");
+    const certPem = fs.readFileSync(certPath, "utf8");
+    const privateKey = forge.pki.privateKeyFromPem(privateKeyPem);
+    const certificate = forge.pki.certificateFromPem(certPem);
+
+    // Don't return a cert that is valid for less than 1 hour
+    const oneHourFromNow = new Date(Date.now() + 60 * 60 * 1000);
+    if (certificate.validity.notAfter > oneHourFromNow) {
+      return { privateKey, certificate };
+    }
+  }
+
+  const { privateKey, certificate } = generateCa();
+  fs.mkdirSync(certFolder, { recursive: true });
+  fs.writeFileSync(keyPath, forge.pki.privateKeyToPem(privateKey));
+  fs.writeFileSync(certPath, forge.pki.certificateToPem(certificate));
+  return { privateKey, certificate };
+}
+
+function generateCa() {
+  const keys = forge.pki.rsa.generateKeyPair(2048);
+  const cert = forge.pki.createCertificate();
+  cert.publicKey = keys.publicKey;
+  cert.serialNumber = "01";
+  cert.validity.notBefore = new Date();
+  cert.validity.notAfter = new Date();
+  cert.validity.notAfter.setDate(cert.validity.notBefore.getDate() + 1);
+
+  const attrs = [{ name: "commonName", value: "safe-chain proxy" }];
+  cert.setSubject(attrs);
+  cert.setIssuer(attrs);
+  cert.setExtensions([
+    {
+      name: "basicConstraints",
+      cA: true,
+    },
+    {
+      name: "keyUsage",
+      keyCertSign: true,
+      digitalSignature: true,
+      keyEncipherment: true,
+    },
+  ]);
+  cert.sign(keys.privateKey, forge.md.sha256.create());
+
+  return {
+    privateKey: keys.privateKey,
+    certificate: cert,
+  };
+}
diff --git a/packages/safe-chain/src/registryProxy/mitmRequestHandler.js b/packages/safe-chain/src/registryProxy/mitmRequestHandler.js
new file mode 100644
index 0000000..4be9987
--- /dev/null
+++ b/packages/safe-chain/src/registryProxy/mitmRequestHandler.js
@@ -0,0 +1,90 @@
+import https from "https";
+import { generateCertForHost } from "./certUtils.js";
+import { HttpsProxyAgent } from "https-proxy-agent";
+
+export function mitmConnect(req, clientSocket, isAllowed) {
+  const { hostname } = new URL(`http://${req.url}`);
+
+  const server = createHttpsServer(hostname, isAllowed);
+
+  // Establish the connection
+  clientSocket.write("HTTP/1.1 200 Connection Established\r\n\r\n");
+
+  // Hand off the socket to the HTTPS server
+  server.emit("connection", clientSocket);
+}
+
+function createHttpsServer(hostname, isAllowed) {
+  const cert = generateCertForHost(hostname);
+
+  async function handleRequest(req, res) {
+    const pathAndQuery = getRequestPathAndQuery(req.url);
+    const targetUrl = `https://${hostname}${pathAndQuery}`;
+
+    if (!(await isAllowed(targetUrl))) {
+      res.writeHead(403, "Forbidden - blocked by safe-chain");
+      res.end("Blocked by safe-chain");
+      return;
+    }
+
+    // Collect request body
+    forwardRequest(req, hostname, res);
+  }
+
+  return https.createServer(
+    {
+      key: cert.privateKey,
+      cert: cert.certificate,
+    },
+    handleRequest
+  );
+}
+
+function getRequestPathAndQuery(url) {
+  if (url.startsWith("http://") || url.startsWith("https://")) {
+    const parsedUrl = new URL(url);
+    return parsedUrl.pathname + parsedUrl.search + parsedUrl.hash;
+  }
+  return url;
+}
+
+function forwardRequest(req, hostname, res) {
+  const proxyReq = createProxyRequest(hostname, req, res);
+
+  proxyReq.on("error", () => {
+    res.writeHead(502);
+    res.end("Bad Gateway");
+  });
+
+  req.on("data", (chunk) => {
+    proxyReq.write(chunk);
+  });
+
+  req.on("end", () => {
+    proxyReq.end();
+  });
+}
+
+function createProxyRequest(hostname, req, res) {
+  const options = {
+    hostname: hostname,
+    port: 443,
+    path: req.url,
+    method: req.method,
+    headers: { ...req.headers },
+  };
+
+  delete options.headers.host;
+
+  const httpsProxy = process.env.HTTPS_PROXY || process.env.https_proxy;
+  if (httpsProxy) {
+    options.agent = new HttpsProxyAgent(httpsProxy);
+  }
+
+  const proxyReq = https.request(options, (proxyRes) => {
+    res.writeHead(proxyRes.statusCode, proxyRes.headers);
+    proxyRes.pipe(res);
+  });
+
+  return proxyReq;
+}
diff --git a/packages/safe-chain/src/registryProxy/parsePackageFromUrl.js b/packages/safe-chain/src/registryProxy/parsePackageFromUrl.js
new file mode 100644
index 0000000..7368b35
--- /dev/null
+++ b/packages/safe-chain/src/registryProxy/parsePackageFromUrl.js
@@ -0,0 +1,48 @@
+export const knownRegistries = ["registry.npmjs.org", "registry.yarnpkg.com"];
+
+export function parsePackageFromUrl(url) {
+  let packageName, version, registry;
+
+  for (const knownRegistry of knownRegistries) {
+    if (url.includes(knownRegistry)) {
+      registry = knownRegistry;
+      break;
+    }
+  }
+
+  if (!registry || !url.endsWith(".tgz")) {
+    return { packageName, version };
+  }
+
+  const registryIndex = url.indexOf(registry);
+  const afterRegistry = url.substring(registryIndex + registry.length + 1); // +1 to skip the slash
+
+  const separatorIndex = afterRegistry.indexOf("/-/");
+  if (separatorIndex === -1) {
+    return { packageName, version };
+  }
+
+  packageName = afterRegistry.substring(0, separatorIndex);
+  const filename = afterRegistry.substring(
+    separatorIndex + 3,
+    afterRegistry.length - 4
+  ); // Remove /-/ and .tgz
+
+  // Extract version from filename
+  // For scoped packages like @babel/core, the filename is core-7.21.4.tgz
+  // For regular packages like lodash, the filename is lodash-4.17.21.tgz
+  if (packageName.startsWith("@")) {
+    const scopedPackageName = packageName.substring(
+      packageName.lastIndexOf("/") + 1
+    );
+    if (filename.startsWith(scopedPackageName + "-")) {
+      version = filename.substring(scopedPackageName.length + 1);
+    }
+  } else {
+    if (filename.startsWith(packageName + "-")) {
+      version = filename.substring(packageName.length + 1);
+    }
+  }
+
+  return { packageName, version };
+}
diff --git a/packages/safe-chain/src/registryProxy/parsePackageFromUrl.spec.js b/packages/safe-chain/src/registryProxy/parsePackageFromUrl.spec.js
new file mode 100644
index 0000000..0b8f700
--- /dev/null
+++ b/packages/safe-chain/src/registryProxy/parsePackageFromUrl.spec.js
@@ -0,0 +1,114 @@
+import { describe, it } from "node:test";
+import assert from "node:assert";
+import { parsePackageFromUrl } from "./parsePackageFromUrl.js";
+
+describe("parsePackageFromUrl", () => {
+  const testCases = [
+    // Regular packages
+    {
+      url: "https://registry.npmjs.org/lodash/-/lodash-4.17.21.tgz",
+      expected: { packageName: "lodash", version: "4.17.21" },
+    },
+    {
+      url: "https://registry.npmjs.org/express/-/express-4.18.2.tgz",
+      expected: { packageName: "express", version: "4.18.2" },
+    },
+    // Packages with hyphens in name
+    {
+      url: "https://registry.npmjs.org/safe-chain-test/-/safe-chain-test-1.0.0.tgz",
+      expected: { packageName: "safe-chain-test", version: "1.0.0" },
+    },
+    {
+      url: "https://registry.npmjs.org/web-vitals/-/web-vitals-3.5.0.tgz",
+      expected: { packageName: "web-vitals", version: "3.5.0" },
+    },
+    // Preview/prerelease versions
+    {
+      url: "https://registry.npmjs.org/safe-chain-test/-/safe-chain-test-0.0.1-security.tgz",
+      expected: { packageName: "safe-chain-test", version: "0.0.1-security" },
+    },
+    {
+      url: "https://registry.npmjs.org/lodash/-/lodash-5.0.0-beta.1.tgz",
+      expected: { packageName: "lodash", version: "5.0.0-beta.1" },
+    },
+    {
+      url: "https://registry.npmjs.org/react/-/react-18.3.0-canary-abc123.tgz",
+      expected: { packageName: "react", version: "18.3.0-canary-abc123" },
+    },
+    // Scoped packages
+    {
+      url: "https://registry.npmjs.org/@babel/core/-/core-7.21.4.tgz",
+      expected: { packageName: "@babel/core", version: "7.21.4" },
+    },
+    {
+      url: "https://registry.npmjs.org/@types/node/-/node-20.10.5.tgz",
+      expected: { packageName: "@types/node", version: "20.10.5" },
+    },
+    {
+      url: "https://registry.npmjs.org/@angular/common/-/common-17.0.8.tgz",
+      expected: { packageName: "@angular/common", version: "17.0.8" },
+    },
+    // Scoped packages with hyphens
+    {
+      url: "https://registry.npmjs.org/@safe-chain/test-package/-/test-package-2.1.0.tgz",
+      expected: { packageName: "@safe-chain/test-package", version: "2.1.0" },
+    },
+    {
+      url: "https://registry.npmjs.org/@aws-sdk/client-s3/-/client-s3-3.465.0.tgz",
+      expected: { packageName: "@aws-sdk/client-s3", version: "3.465.0" },
+    },
+    // Scoped packages with preview versions
+    {
+      url: "https://registry.npmjs.org/@babel/core/-/core-8.0.0-alpha.1.tgz",
+      expected: { packageName: "@babel/core", version: "8.0.0-alpha.1" },
+    },
+    {
+      url: "https://registry.npmjs.org/@safe-chain/security-test/-/security-test-1.0.0-security.tgz",
+      expected: {
+        packageName: "@safe-chain/security-test",
+        version: "1.0.0-security",
+      },
+    },
+    // Yarn registry
+    {
+      url: "https://registry.yarnpkg.com/lodash/-/lodash-4.17.21.tgz",
+      expected: { packageName: "lodash", version: "4.17.21" },
+    },
+    {
+      url: "https://registry.yarnpkg.com/@babel/core/-/core-7.21.4.tgz",
+      expected: { packageName: "@babel/core", version: "7.21.4" },
+    },
+    // Invalid URLs should return undefined values
+    {
+      url: "https://example.com/package.tgz",
+      expected: { packageName: undefined, version: undefined },
+    },
+    // URL to get package info, not tarball
+    {
+      url: "https://registry.npmjs.org/lodash",
+      expected: { packageName: undefined, version: undefined },
+    },
+    // Complex version patterns
+    {
+      url: "https://registry.npmjs.org/package-with-many-hyphens/-/package-with-many-hyphens-1.0.0-rc.1+build.123.tgz",
+      expected: {
+        packageName: "package-with-many-hyphens",
+        version: "1.0.0-rc.1+build.123",
+      },
+    },
+    {
+      url: "https://registry.npmjs.org/@scope/package-name-with-hyphens/-/package-name-with-hyphens-2.0.0-beta.2.tgz",
+      expected: {
+        packageName: "@scope/package-name-with-hyphens",
+        version: "2.0.0-beta.2",
+      },
+    },
+  ];
+
+  testCases.forEach(({ url, expected }, index) => {
+    it(`should parse URL ${index + 1}: ${url}`, () => {
+      const result = parsePackageFromUrl(url);
+      assert.deepEqual(result, expected);
+    });
+  });
+});
diff --git a/packages/safe-chain/src/registryProxy/registryProxy.js b/packages/safe-chain/src/registryProxy/registryProxy.js
new file mode 100644
index 0000000..3558673
--- /dev/null
+++ b/packages/safe-chain/src/registryProxy/registryProxy.js
@@ -0,0 +1,158 @@
+import * as http from "http";
+import { tunnelRequest } from "./tunnelRequestHandler.js";
+import { mitmConnect } from "./mitmRequestHandler.js";
+import { getCaCertPath } from "./certUtils.js";
+import { auditChanges } from "../scanning/audit/index.js";
+import { knownRegistries, parsePackageFromUrl } from "./parsePackageFromUrl.js";
+import { ui } from "../environment/userInteraction.js";
+import chalk from "chalk";
+
+const SERVER_STOP_TIMEOUT_MS = 1000;
+const state = {
+  port: null,
+  blockedRequests: [],
+};
+
+export function createSafeChainProxy() {
+  const server = createProxyServer();
+  server.on("connect", handleConnect);
+
+  return {
+    startServer: () => startServer(server),
+    stopServer: () => stopServer(server),
+    verifyNoMaliciousPackages,
+  };
+}
+
+function getSafeChainProxyEnvironmentVariables() {
+  if (!state.port) {
+    return {};
+  }
+
+  return {
+    HTTPS_PROXY: `http://localhost:${state.port}`,
+    GLOBAL_AGENT_HTTP_PROXY: `http://localhost:${state.port}`,
+    NODE_EXTRA_CA_CERTS: getCaCertPath(),
+  };
+}
+
+export function mergeSafeChainProxyEnvironmentVariables(env) {
+  const proxyEnv = getSafeChainProxyEnvironmentVariables();
+
+  for (const key of Object.keys(env)) {
+    // If we were to simply copy all env variables, we might overwrite
+    // the proxy settings set by safe-chain when casing varies (e.g. http_proxy vs HTTP_PROXY)
+    // So we only copy the variable if it's not already set in a different case
+    const upperKey = key.toUpperCase();
+
+    if (!proxyEnv[upperKey]) {
+      proxyEnv[key] = env[key];
+    }
+  }
+
+  return proxyEnv;
+}
+
+function createProxyServer() {
+  const server = http.createServer((_, res) => {
+    res.writeHead(400, "Bad Request");
+    res.write(
+      "Safe-chain proxy: Direct http not supported. Only CONNECT requests are allowed."
+    );
+    res.end();
+  });
+
+  return server;
+}
+
+function startServer(server) {
+  return new Promise((resolve, reject) => {
+    // Passing port 0 makes the OS assign an available port
+    server.listen(0, () => {
+      const address = server.address();
+      if (address && typeof address === "object") {
+        state.port = address.port;
+        resolve();
+      } else {
+        reject(new Error("Failed to start proxy server"));
+      }
+    });
+
+    server.on("error", (err) => {
+      reject(err);
+    });
+  });
+}
+
+function stopServer(server) {
+  return new Promise((resolve) => {
+    try {
+      server.close(() => {
+        resolve();
+      });
+    } catch {
+      resolve();
+    }
+    setTimeout(() => resolve(), SERVER_STOP_TIMEOUT_MS);
+  });
+}
+
+function handleConnect(req, clientSocket, head) {
+  // CONNECT method is used for HTTPS requests
+  // It establishes a tunnel to the server identified by the request URL
+
+  if (knownRegistries.some((reg) => req.url.includes(reg))) {
+    // For npm and yarn registries, we want to intercept and inspect the traffic
+    // so we can block packages with malware
+    mitmConnect(req, clientSocket, isAllowedUrl);
+  } else {
+    // For other hosts, just tunnel the request to the destination tcp socket
+    tunnelRequest(req, clientSocket, head);
+  }
+}
+
+async function isAllowedUrl(url) {
+  const { packageName, version } = parsePackageFromUrl(url);
+
+  // packageName and version are undefined when the URL is not a package download
+  // In that case, we can allow the request to proceed
+  if (!packageName || !version) {
+    return true;
+  }
+
+  const auditResult = await auditChanges([
+    { name: packageName, version, type: "add" },
+  ]);
+
+  if (!auditResult.isAllowed) {
+    state.blockedRequests.push({ packageName, version, url });
+    return false;
+  }
+
+  return true;
+}
+
+function verifyNoMaliciousPackages() {
+  if (state.blockedRequests.length === 0) {
+    // No malicious packages were blocked, so nothing to block
+    return true;
+  }
+
+  ui.emptyLine();
+
+  ui.writeInformation(
+    `Safe-chain: ${chalk.bold(
+      `blocked ${state.blockedRequests.length} malicious package downloads`
+    )}:`
+  );
+
+  for (const req of state.blockedRequests) {
+    ui.writeInformation(` - ${req.packageName}@${req.version} (${req.url})`);
+  }
+
+  ui.emptyLine();
+  ui.writeError("Exiting without installing malicious packages.");
+  ui.emptyLine();
+
+  return false;
+}
diff --git a/packages/safe-chain/src/registryProxy/tunnelRequestHandler.js b/packages/safe-chain/src/registryProxy/tunnelRequestHandler.js
new file mode 100644
index 0000000..95e2beb
--- /dev/null
+++ b/packages/safe-chain/src/registryProxy/tunnelRequestHandler.js
@@ -0,0 +1,98 @@
+import * as net from "net";
+import { ui } from "../environment/userInteraction.js";
+
+export function tunnelRequest(req, clientSocket, head) {
+  const httpsProxy = process.env.HTTPS_PROXY || process.env.https_proxy;
+
+  if (httpsProxy) {
+    // If an HTTPS proxy is set, tunnel the request via the proxy
+    // This is the system proxy, not the safe-chain proxy
+    // The package manager will run via the safe-chain proxy
+    // The safe-chain proxy will then send the request to the system proxy
+    // Typical flow: package manager -> safe-chain proxy -> system proxy -> destination
+
+    // There are 2 processes involved in this:
+    // 1. Safe-chain process: has HTTPS_PROXY set to system proxy
+    // 2. Package manager process: has HTTPS_PROXY set to safe-chain proxy
+
+    tunnelRequestViaProxy(req, clientSocket, head, httpsProxy);
+  } else {
+    tunnelRequestToDestination(req, clientSocket, head);
+  }
+}
+
+function tunnelRequestToDestination(req, clientSocket, head) {
+  const { port, hostname } = new URL(`http://${req.url}`);
+
+  const serverSocket = net.connect(port || 443, hostname, () => {
+    clientSocket.write("HTTP/1.1 200 Connection Established\r\n\r\n");
+    serverSocket.write(head);
+    serverSocket.pipe(clientSocket);
+    clientSocket.pipe(serverSocket);
+  });
+
+  serverSocket.on("error", (err) => {
+    ui.writeError(
+      `Safe-chain: error connecting to ${hostname}:${port} - ${err.message}`
+    );
+    clientSocket.end("HTTP/1.1 502 Bad Gateway\r\n\r\n");
+  });
+}
+
+function tunnelRequestViaProxy(req, clientSocket, head, proxyUrl) {
+  const { port, hostname } = new URL(`http://${req.url}`);
+  const proxy = new URL(proxyUrl);
+
+  // Connect to proxy server
+  const proxySocket = net.connect({
+    host: proxy.hostname,
+    port: proxy.port,
+  });
+
+  proxySocket.on("connect", () => {
+    // Send CONNECT request to proxy
+    const connectRequest = [
+      `CONNECT ${hostname}:${port || 443} HTTP/1.1`,
+      `Host: ${hostname}:${port || 443}`,
+      "",
+      "",
+    ].join("\r\n");
+
+    proxySocket.write(connectRequest);
+  });
+
+  let isConnected = false;
+  proxySocket.once("data", (data) => {
+    const response = data.toString();
+
+    // Check if CONNECT succeeded (HTTP/1.1 200)
+    if (response.startsWith("HTTP/1.1 200")) {
+      isConnected = true;
+      clientSocket.write("HTTP/1.1 200 Connection Established\r\n\r\n");
+      proxySocket.write(head);
+      proxySocket.pipe(clientSocket);
+      clientSocket.pipe(proxySocket);
+    } else {
+      ui.writeError(
+        `Safe-chain: proxy CONNECT failed: ${response.split("\r\n")[0]}`
+      );
+      clientSocket.end("HTTP/1.1 502 Bad Gateway\r\n\r\n");
+      proxySocket.end();
+    }
+  });
+
+  proxySocket.on("error", (err) => {
+    if (!isConnected) {
+      ui.writeError(
+        `Safe-chain: error connecting to proxy ${proxy.hostname}:${
+          proxy.port || 8080
+        } - ${err.message}`
+      );
+      clientSocket.end("HTTP/1.1 502 Bad Gateway\r\n\r\n");
+    }
+  });
+
+  clientSocket.on("error", () => {
+    proxySocket.end();
+  });
+}
diff --git a/packages/safe-chain/src/scanning/index.js b/packages/safe-chain/src/scanning/index.js
index 48a3e3a..36f62ca 100644
--- a/packages/safe-chain/src/scanning/index.js
+++ b/packages/safe-chain/src/scanning/index.js
@@ -61,10 +61,11 @@ export async function scanCommand(args) {
   }
 
   if (!audit || audit.isAllowed) {
-    spinner.succeed("Safe-chain: No malicious packages detected.");
+    spinner.stop();
+    return 0;
   } else {
     printMaliciousChanges(audit.disallowedChanges, spinner);
-    await onMalwareFound();
+    return await onMalwareFound();
   }
 }
 
@@ -88,11 +89,11 @@ async function onMalwareFound() {
 
     if (continueInstall) {
       ui.writeWarning("Continuing with the installation despite the risks...");
-      return;
+      return 0;
     }
   }
 
   ui.writeError("Exiting without installing malicious packages.");
   ui.emptyLine();
-  process.exit(1);
+  return 1;
 }
diff --git a/packages/safe-chain/src/scanning/index.scanCommand.spec.js b/packages/safe-chain/src/scanning/index.scanCommand.spec.js
index 715ecfb..1858d10 100644
--- a/packages/safe-chain/src/scanning/index.scanCommand.spec.js
+++ b/packages/safe-chain/src/scanning/index.scanCommand.spec.js
@@ -1,5 +1,5 @@
 import assert from "node:assert/strict";
-import { describe, it, mock } from "node:test";
+import { beforeEach, describe, it, mock } from "node:test";
 import { setTimeout } from "node:timers/promises";
 import {
   MALWARE_ACTION_PROMPT,
@@ -13,6 +13,7 @@ describe("scanCommand", async () => {
     setText: () => {},
     succeed: () => {},
     fail: () => {},
+    stop: () => {},
   }));
   const mockConfirm = mock.fn(() => true);
   let malwareAction = MALWARE_ACTION_PROMPT;
@@ -87,30 +88,37 @@ describe("scanCommand", async () => {
 
   const { scanCommand } = await import("./index.js");
 
+  beforeEach(() => {
+    // Reset malware action back to prompt mode for other tests
+    malwareAction = MALWARE_ACTION_PROMPT;
+  });
+
   it("should succeed when there are no changes", async () => {
-    let successMessageWasSet = false;
+    let progressWasStopped = false;
     mockStartProcess.mock.mockImplementationOnce(() => ({
       setText: () => {},
-      succeed: () => {
-        successMessageWasSet = true;
-      },
+      succeed: () => {},
       fail: () => {},
+      stop: () => {
+        progressWasStopped = true;
+      },
     }));
     mockGetDependencyUpdatesForCommand.mock.mockImplementation(() => []);
 
     await scanCommand(["install", "lodash"]);
 
-    assert.equal(successMessageWasSet, true);
+    assert.equal(progressWasStopped, true);
   });
 
   it("should succeed when changes are not malicious", async () => {
-    let successMessageWasSet = false;
+    let progressWasStopped = false;
     mockStartProcess.mock.mockImplementationOnce(() => ({
       setText: () => {},
-      succeed: () => {
-        successMessageWasSet = true;
-      },
+      succeed: () => {},
       fail: () => {},
+      stop: () => {
+        progressWasStopped = true;
+      },
     }));
     mockGetDependencyUpdatesForCommand.mock.mockImplementation(() => [
       { name: "lodash", version: "4.17.21" },
@@ -118,7 +126,7 @@ describe("scanCommand", async () => {
 
     await scanCommand(["install", "lodash"]);
 
-    assert.equal(successMessageWasSet, true);
+    assert.equal(progressWasStopped, true);
   });
 
   it("should throw an error when timing out", async () => {
@@ -129,6 +137,7 @@ describe("scanCommand", async () => {
       fail: () => {
         failureMessageWasSet = true;
       },
+      stop: () => {},
     }));
     getScanTimeoutMock.mock.mockImplementationOnce(() => 100);
     mockGetDependencyUpdatesForCommand.mock.mockImplementation(async () => {
@@ -149,6 +158,7 @@ describe("scanCommand", async () => {
       fail: () => {
         failureMessageWasSet = true;
       },
+      stop: () => {},
     }));
     mockGetDependencyUpdatesForCommand.mock.mockImplementation(() => [
       { name: "malicious", version: "1.0.0" },
@@ -173,6 +183,7 @@ describe("scanCommand", async () => {
       fail: (message) => {
         failureMessages.push(message);
       },
+      stop: () => {},
     }));
     getScanTimeoutMock.mock.mockImplementationOnce(() => 100);
     mockGetDependencyUpdatesForCommand.mock.mockImplementation(async () => {
@@ -194,46 +205,29 @@ describe("scanCommand", async () => {
   it("should exit immediately when malicious changes are detected in block mode", async () => {
     // Set malware action to block mode for this test
     malwareAction = MALWARE_ACTION_BLOCK;
-    
+
     // Reset mock call count
     mockConfirm.mock.resetCalls();
-    
+
     let failureMessageWasSet = false;
-    let exitCode = null;
-    
+
     mockStartProcess.mock.mockImplementationOnce(() => ({
       setText: () => {},
       succeed: () => {},
       fail: () => {
         failureMessageWasSet = true;
       },
+      stop: () => {},
     }));
-    
+
     mockGetDependencyUpdatesForCommand.mock.mockImplementation(() => [
       { name: "malicious", version: "1.0.0" },
     ]);
 
-    // Mock process.exit
-    const originalExit = process.exit;
-    process.exit = mock.fn((code) => {
-      exitCode = code;
-      throw new Error("Process exit called"); // Prevent actual exit
-    });
-
-    try {
-      await assert.rejects(
-        scanCommand(["install", "malicious"]),
-        /Process exit called/
-      );
-    } finally {
-      // Restore original process.exit
-      process.exit = originalExit;
-      // Reset malware action back to prompt mode for other tests
-      malwareAction = MALWARE_ACTION_PROMPT;
-    }
+    const result = await scanCommand(["install", "malicious"]);
 
     assert.equal(failureMessageWasSet, true);
-    assert.equal(exitCode, 1);
+    assert.equal(result, 1);
     // Confirm should not have been called in block mode
     assert.equal(mockConfirm.mock.callCount(), 0);
   });
@@ -241,19 +235,19 @@ describe("scanCommand", async () => {
   it("should exit immediately when malicious changes are detected in block mode without prompting", async () => {
     // Set malware action to block mode for this test
     malwareAction = MALWARE_ACTION_BLOCK;
-    
+
     // Reset mock call count
     mockConfirm.mock.resetCalls();
-    
-    let processExited = false;
+
     let userWasPrompted = false;
-    
+
     mockStartProcess.mock.mockImplementationOnce(() => ({
       setText: () => {},
       succeed: () => {},
       fail: () => {},
+      stop: () => {},
     }));
-    
+
     mockGetDependencyUpdatesForCommand.mock.mockImplementation(() => [
       { name: "malicious", version: "1.0.0" },
     ]);
@@ -263,26 +257,9 @@ describe("scanCommand", async () => {
       return false;
     });
 
-    // Mock process.exit
-    const originalExit = process.exit;
-    process.exit = mock.fn(() => {
-      processExited = true;
-      throw new Error("Process exit called"); // Prevent actual exit
-    });
+    const result = await scanCommand(["install", "malicious"]);
 
-    try {
-      await assert.rejects(
-        scanCommand(["install", "malicious"]),
-        /Process exit called/
-      );
-    } finally {
-      // Restore original process.exit
-      process.exit = originalExit;
-      // Reset malware action back to prompt mode for other tests
-      malwareAction = MALWARE_ACTION_PROMPT;
-    }
-
-    assert.equal(processExited, true);
+    assert.equal(result, 1);
     assert.equal(userWasPrompted, false);
   });
 });
diff --git a/packages/safe-chain/src/scanning/malwareDatabase.js b/packages/safe-chain/src/scanning/malwareDatabase.js
index 26f1999..1cb781b 100644
--- a/packages/safe-chain/src/scanning/malwareDatabase.js
+++ b/packages/safe-chain/src/scanning/malwareDatabase.js
@@ -8,7 +8,13 @@ import {
 } from "../config/configFile.js";
 import { ui } from "../environment/userInteraction.js";
 
+let cachedMalwareDatabase = null;
+
 export async function openMalwareDatabase() {
+  if (cachedMalwareDatabase) {
+    return cachedMalwareDatabase;
+  }
+
   const malwareDatabase = await getMalwareDatabase();
 
   function getPackageStatus(name, version) {
@@ -25,13 +31,16 @@ export async function openMalwareDatabase() {
     return packageData.reason;
   }
 
-  return {
+  // This implicitely caches the malware database
+  //  that's closed over by the getPackageStatus function
+  cachedMalwareDatabase = {
     getPackageStatus,
     isMalware: (name, version) => {
       const status = getPackageStatus(name, version);
       return isMalwareStatus(status);
     },
   };
+  return cachedMalwareDatabase;
 }
 
 async function getMalwareDatabase() {
diff --git a/packages/safe-chain/src/utils/safeSpawn.js b/packages/safe-chain/src/utils/safeSpawn.js
index 826ab7d..c5cd913 100644
--- a/packages/safe-chain/src/utils/safeSpawn.js
+++ b/packages/safe-chain/src/utils/safeSpawn.js
@@ -23,11 +23,23 @@ export async function safeSpawn(command, args, options = {}) {
   return new Promise((resolve, reject) => {
     const child = spawn(fullCommand, { ...options, shell: true });
 
+    // When stdio is piped, we need to collect the output
+    let stdout = "";
+    let stderr = "";
+
+    child.stdout?.on("data", (data) => {
+      stdout += data.toString();
+    });
+
+    child.stderr?.on("data", (data) => {
+      stderr += data.toString();
+    });
+
     child.on("close", (code) => {
       resolve({
         status: code,
-        stdout: Buffer.from(""),
-        stderr: Buffer.from(""),
+        stdout: stdout,
+        stderr: stderr,
       });
     });
 
diff --git a/test/e2e/Dockerfile b/test/e2e/Dockerfile
index a84db30..3c8ce73 100644
--- a/test/e2e/Dockerfile
+++ b/test/e2e/Dockerfile
@@ -29,6 +29,9 @@ ARG PNPM_VERSION=latest
 SHELL ["/bin/bash", "-c"]
 ENV BASH_ENV=~/.bashrc
 
+# Install a proxy
+RUN apt-get update && apt-get install tinyproxy -y
+
 # Install zsh
 RUN sh -c "$(wget -O- https://github.com/deluan/zsh-in-docker/releases/download/v1.2.1/zsh-in-docker.sh)"
 # Install fish
diff --git a/test/e2e/npm-ci.e2e.spec.js b/test/e2e/npm-ci.e2e.spec.js
index 3e08c3d..dc1c23f 100644
--- a/test/e2e/npm-ci.e2e.spec.js
+++ b/test/e2e/npm-ci.e2e.spec.js
@@ -36,7 +36,7 @@ describe("E2E: npm coverage using PATH", () => {
     const result = await shell.runCommand("npm i axios");
 
     assert.ok(
-      result.output.includes("No malicious packages detected."),
+      result.output.includes("no malicious packages found."),
       `Output did not include expected text. Output was:\n${result.output}`
     );
   });
diff --git a/test/e2e/npm.e2e.spec.js b/test/e2e/npm.e2e.spec.js
index 0e64971..c744835 100644
--- a/test/e2e/npm.e2e.spec.js
+++ b/test/e2e/npm.e2e.spec.js
@@ -31,7 +31,7 @@ describe("E2E: npm coverage", () => {
     const result = await shell.runCommand("npm i axios");
 
     assert.ok(
-      result.output.includes("No malicious packages detected."),
+      result.output.includes("no malicious packages found."),
       `Output did not include expected text. Output was:\n${result.output}`
     );
   });
@@ -60,6 +60,52 @@ describe("E2E: npm coverage", () => {
     );
   });
 
+  it(`safe-chain blocks download of malicious packages already in package.json`, async () => {
+    const shell = await container.openShell("zsh");
+    const npmVersion = (await shell.runCommand("npm --version")).output.trim();
+    const majorVersion = parseInt(npmVersion.split(".")[0]);
+    const minorVersion = parseInt(npmVersion.split(".")[1]);
+    const isBelow10_4 =
+      majorVersion < 10 || (majorVersion === 10 && minorVersion < 4);
+    await shell.runCommand(
+      'echo \'{"name":"test-project","version":"1.0.0","dependencies":{"safe-chain-test":"0.0.1-security"}}\' > package.json'
+    );
+
+    var result = await shell.runCommand("npm install");
+
+    if (isBelow10_4) {
+      assert.ok(
+        result.output.includes("blocked 1 malicious package downloads"),
+        `Output did not include expected text. Output was:\n${result.output}`
+      );
+      assert.ok(
+        result.output.includes("- safe-chain-test"),
+        `Output did not include expected text. Output was:\n${result.output}`
+      );
+      assert.ok(
+        result.output.includes(
+          "Exiting without installing malicious packages."
+        ),
+        `Output did not include expected text. Output was:\n${result.output}`
+      );
+    } else {
+      assert.ok(
+        result.output.includes("Malicious changes detected:"),
+        `Output did not include expected text. Output was:\n${result.output}`
+      );
+      assert.ok(
+        result.output.includes("- safe-chain-test"),
+        `Output did not include expected text. Output was:\n${result.output}`
+      );
+      assert.ok(
+        result.output.includes(
+          "Exiting without installing malicious packages."
+        ),
+        `Output did not include expected text. Output was:\n${result.output}`
+      );
+    }
+  });
+
   it("safe-chain blocks npx from executing malicious packages", async () => {
     const shell = await container.openShell("zsh");
     const result = await shell.runCommand("npx safe-chain-test");
diff --git a/test/e2e/package.json b/test/e2e/package.json
index 1dc6e8a..9217808 100644
--- a/test/e2e/package.json
+++ b/test/e2e/package.json
@@ -4,7 +4,7 @@
   "version": "1.0.0",
   "description": "End-to-end tests for the Aikido Safe Chain",
   "scripts": {
-    "test": "node --test **/*.spec.js"
+    "test": "node --test --test-concurrency=1 **/*.spec.js"
   },
   "keywords": [],
   "author": "Aikido Security",
diff --git a/test/e2e/pnpm-ci.e2e.spec.js b/test/e2e/pnpm-ci.e2e.spec.js
index 9a8c6a2..339a5e0 100644
--- a/test/e2e/pnpm-ci.e2e.spec.js
+++ b/test/e2e/pnpm-ci.e2e.spec.js
@@ -36,7 +36,7 @@ describe("E2E: pnpm coverage", () => {
     const result = await shell.runCommand("pnpm add axios");
 
     assert.ok(
-      result.output.includes("No malicious packages detected."),
+      result.output.includes("no malicious packages found."),
       `Output did not include expected text. Output was:\n${result.output}`
     );
   });
diff --git a/test/e2e/pnpm.e2e.spec.js b/test/e2e/pnpm.e2e.spec.js
index db7eb58..c0187d7 100644
--- a/test/e2e/pnpm.e2e.spec.js
+++ b/test/e2e/pnpm.e2e.spec.js
@@ -31,7 +31,7 @@ describe("E2E: pnpm coverage", () => {
     const result = await shell.runCommand("pnpm add axios");
 
     assert.ok(
-      result.output.includes("No malicious packages detected."),
+      result.output.includes("no malicious packages found."),
       `Output did not include expected text. Output was:\n${result.output}`
     );
   });
@@ -60,6 +60,28 @@ describe("E2E: pnpm coverage", () => {
     );
   });
 
+  it(`safe-chain blocks download of malicious packages already in package.json`, async () => {
+    const shell = await container.openShell("zsh");
+    await shell.runCommand(
+      'echo \'{"name":"test-project","version":"1.0.0","dependencies":{"safe-chain-test":"0.0.1-security"}}\' > package.json'
+    );
+
+    var result = await shell.runCommand("pnpm install");
+
+    assert.ok(
+      result.output.includes("blocked 1 malicious package downloads"),
+      `Output did not include expected text. Output was:\n${result.output}`
+    );
+    assert.ok(
+      result.output.includes("- safe-chain-test"),
+      `Output did not include expected text. Output was:\n${result.output}`
+    );
+    assert.ok(
+      result.output.includes("Exiting without installing malicious packages."),
+      `Output did not include expected text. Output was:\n${result.output}`
+    );
+  });
+
   it("safe-chain blocks pnpx from executing malicious packages", async () => {
     const shell = await container.openShell("zsh");
     const result = await shell.runCommand("pnpx safe-chain-test");
diff --git a/test/e2e/safe-chain-proxy.e2e.spec.js b/test/e2e/safe-chain-proxy.e2e.spec.js
new file mode 100644
index 0000000..6abbb0f
--- /dev/null
+++ b/test/e2e/safe-chain-proxy.e2e.spec.js
@@ -0,0 +1,60 @@
+import { describe, it, before, beforeEach, afterEach } from "node:test";
+import { DockerTestContainer } from "./DockerTestContainer.js";
+import assert from "node:assert";
+
+describe("E2E: Safe chain proxy", () => {
+  let container;
+
+  before(async () => {
+    DockerTestContainer.buildImage();
+  });
+
+  beforeEach(async () => {
+    // Run a new Docker container for each test
+    container = new DockerTestContainer();
+    await container.start();
+
+    const installationShell = await container.openShell("zsh");
+    await installationShell.runCommand("safe-chain setup");
+  });
+
+  afterEach(async () => {
+    // Stop and clean up the container after each test
+    if (container) {
+      await container.stop();
+      container = null;
+    }
+  });
+
+  it(`safe-chain proxy respects upstream proxy settings`, async () => {
+    // Configure and start a proxy inside the container
+    const proxy = await container.openShell("zsh");
+    await proxy.runCommand(
+      `echo 'BasicAuth user password' >> /etc/tinyproxy/tinyproxy.conf`
+    );
+    await proxy.runCommand("tinyproxy");
+
+    const shell = await container.openShell("zsh");
+    await shell.runCommand(
+      'export HTTPS_PROXY="http://user:password@localhost:8888"'
+    );
+    const { output } = await shell.runCommand("npm install axios");
+
+    // Check if the installation was successful
+    assert(
+      output.includes("added") || output.includes("up to date"),
+      "npm install did not complete successfully"
+    );
+
+    const proxyLog = await container.openShell("zsh");
+    const { output: logOutput } = await proxyLog.runCommand(
+      "cat /var/log/tinyproxy/tinyproxy.log"
+    );
+
+    // Check if the proxy log contains entries for the npm install
+    assert(
+      logOutput.includes("CONNECT registry.npmjs.org:443"),
+      "Proxy log does not contain expected entries"
+    );
+  });
+});
diff --git a/test/e2e/yarn-ci.e2e.spec.js b/test/e2e/yarn-ci.e2e.spec.js
index 5466851..33ef4f2 100644
--- a/test/e2e/yarn-ci.e2e.spec.js
+++ b/test/e2e/yarn-ci.e2e.spec.js
@@ -36,7 +36,7 @@ describe("E2E: yarn coverage", () => {
     const result = await shell.runCommand("yarn add axios");
 
     assert.ok(
-      result.output.includes("No malicious packages detected."),
+      result.output.includes("no malicious packages found."),
       `Output did not include expected text. Output was:\n${result.output}`
     );
   });
diff --git a/test/e2e/yarn.e2e.spec.js b/test/e2e/yarn.e2e.spec.js
index fb22b76..3909318 100644
--- a/test/e2e/yarn.e2e.spec.js
+++ b/test/e2e/yarn.e2e.spec.js
@@ -31,7 +31,53 @@ describe("E2E: yarn coverage", () => {
     const result = await shell.runCommand("yarn add axios");
 
     assert.ok(
-      result.output.includes("No malicious packages detected."),
+      result.output.includes("no malicious packages found."),
+      `Output did not include expected text. Output was:\n${result.output}`
+    );
+  });
+
+  it(`safe-chain blocks installation of malicious packages`, async () => {
+    const shell = await container.openShell("zsh");
+    const result = await shell.runCommand("yarn add safe-chain-test");
+
+    assert.ok(
+      result.output.includes("Malicious changes detected:"),
+      `Output did not include expected text. Output was:\n${result.output}`
+    );
+    assert.ok(
+      result.output.includes("- safe-chain-test"),
+      `Output did not include expected text. Output was:\n${result.output}`
+    );
+    assert.ok(
+      result.output.includes("Exiting without installing malicious packages."),
+      `Output did not include expected text. Output was:\n${result.output}`
+    );
+
+    const listResult = await shell.runCommand("yarn list");
+    assert.ok(
+      !listResult.output.includes("safe-chain-test"),
+      `Malicious package was installed despite safe-chain protection. Output of 'yarn list' was:\n${listResult.output}`
+    );
+  });
+
+  it(`safe-chain blocks download of malicious packages already in package.json`, async () => {
+    const shell = await container.openShell("zsh");
+    await shell.runCommand(
+      'echo \'{"name":"test-project","version":"1.0.0","dependencies":{"safe-chain-test":"0.0.1-security"}}\' > package.json'
+    );
+
+    var result = await shell.runCommand("yarn");
+
+    assert.ok(
+      result.output.includes("blocked 1 malicious package downloads"),
+      `Output did not include expected text. Output was:\n${result.output}`
+    );
+    assert.ok(
+      result.output.includes("- safe-chain-test"),
+      `Output did not include expected text. Output was:\n${result.output}`
+    );
+    assert.ok(
+      result.output.includes("Exiting without installing malicious packages."),
       `Output did not include expected text. Output was:\n${result.output}`
     );
   });