Clear-text protocols such as ftp, telnet, or http lack encryption of transported data, as well as the
capability to build an authenticated connection. It means that an attacker able to sniff traffic from the network can read, modify, or corrupt the
transported content. These protocols are not secure as they expose applications to an extensive range of risks:
- sensitive data exposure
- traffic redirected to a malicious endpoint
- malware-infected software update or installer
- execution of client-side code
- corruption of critical information
Even in the context of isolated networks like offline environments or segmented cloud environments, the insider threat exists. Thus, attacks
involving communications being sniffed or tampered with can still happen.
For example, attackers could successfully compromise prior security layers by:
- bypassing isolation mechanisms
- compromising a component of the network
- getting the credentials of an internal IAM account (either from a service account or an actual person)
In such cases, encrypting communications would decrease the chances of attackers to successfully leak data or steal credentials from other network
components. By layering various security practices (segmentation and encryption, for example), the application will follow the
defense-in-depth principle.
Note that using the http protocol is being deprecated by major web browsers.
In the past, it has led to the following vulnerabilities:
Ask Yourself Whether
- Application data needs to be protected against falsifications or leaks when transiting over the network.
- Application data transits over an untrusted network.
- Compliance rules require the service to encrypt data in transit.
- Your application renders web pages with a relaxed mixed content policy.
- OS-level protections against clear-text traffic are deactivated.
There is a risk if you answered yes to any of those questions.
Recommended Secure Coding Practices
- Make application data transit over a secure, authenticated and encrypted protocol like TLS or SSH. Here are a few alternatives to the most
common clear-text protocols:
- Use
ssh as an alternative to telnet.
- Use
sftp, scp, or ftps instead of ftp.
- Use
https instead of http.
- Use
SMTP over SSL/TLS or SMTP with STARTTLS instead of clear-text SMTP.
- Enable encryption of cloud components communications whenever it is possible.
- Configure your application to block mixed content when rendering web pages.
- If available, enforce OS-level deactivation of all clear-text traffic.
It is recommended to secure all transport channels, even on local networks, as it can take a single non-secure connection to compromise an entire
application or system.
Sensitive Code Example
url = "http://example.com"; // Sensitive
url = "ftp://anonymous@example.com"; // Sensitive
url = "telnet://anonymous@example.com"; // Sensitive
For nodemailer:
const nodemailer = require("nodemailer");
let transporter = nodemailer.createTransport({
secure: false, // Sensitive
requireTLS: false // Sensitive
});
const nodemailer = require("nodemailer");
let transporter = nodemailer.createTransport({}); // Sensitive
For ftp:
var Client = require('ftp');
var c = new Client();
c.connect({
'secure': false // Sensitive
});
For telnet-client:
const Telnet = require('telnet-client'); // Sensitive
For aws-cdk-lib.aws-elasticloadbalancingv2.ApplicationLoadBalancer:
import { ApplicationLoadBalancer } from 'aws-cdk-lib/aws-elasticloadbalancingv2';
const alb = new ApplicationLoadBalancer(this, 'ALB', {
vpc: vpc,
internetFacing: true
});
alb.addListener('listener-http-default', {
port: 8080,
open: true
}); // Sensitive
alb.addListener('listener-http-explicit', {
protocol: ApplicationProtocol.HTTP, // Sensitive
port: 8080,
open: true
});
For aws-cdk-lib.aws-elasticloadbalancingv2.ApplicationListener:
import { ApplicationListener } from 'aws-cdk-lib/aws-elasticloadbalancingv2';
new ApplicationListener(this, 'listener-http-explicit-constructor', {
loadBalancer: alb,
protocol: ApplicationProtocol.HTTP, // Sensitive
port: 8080,
open: true
});
For aws-cdk-lib.aws-elasticloadbalancingv2.NetworkLoadBalancer:
import { NetworkLoadBalancer } from 'aws-cdk-lib/aws-elasticloadbalancingv2';
const nlb = new NetworkLoadBalancer(this, 'nlb', {
vpc: vpc,
internetFacing: true
});
var listenerNLB = nlb.addListener('listener-tcp-default', {
port: 1234
}); // Sensitive
listenerNLB = nlb.addListener('listener-tcp-explicit', {
protocol: Protocol.TCP, // Sensitive
port: 1234
});
For aws-cdk-lib.aws-elasticloadbalancingv2.NetworkListener:
import { NetworkListener } from 'aws-cdk-lib/aws-elasticloadbalancingv2';
new NetworkListener(this, 'listener-tcp-explicit-constructor', {
loadBalancer: nlb,
protocol: Protocol.TCP, // Sensitive
port: 8080
});
For aws-cdk-lib.aws-elasticloadbalancingv2.CfnListener:
import { CfnListener } from 'aws-cdk-lib/aws-elasticloadbalancingv2';
new CfnListener(this, 'listener-http', {
defaultActions: defaultActions,
loadBalancerArn: alb.loadBalancerArn,
protocol: "HTTP", // Sensitive
port: 80
});
new CfnListener(this, 'listener-tcp', {
defaultActions: defaultActions,
loadBalancerArn: alb.loadBalancerArn,
protocol: "TCP", // Sensitive
port: 80
});
For aws-cdk-lib.aws-elasticloadbalancing.CfnLoadBalancer:
import { CfnLoadBalancer } from 'aws-cdk-lib/aws-elasticloadbalancing';
new CfnLoadBalancer(this, 'elb-tcp', {
listeners: [{
instancePort: '1000',
loadBalancerPort: '1000',
protocol: 'tcp' // Sensitive
}]
});
new CfnLoadBalancer(this, 'elb-http', {
listeners: [{
instancePort: '1000',
loadBalancerPort: '1000',
protocol: 'http' // Sensitive
}]
});
For aws-cdk-lib.aws-elasticloadbalancing.LoadBalancer:
import { LoadBalancer } from 'aws-cdk-lib/aws-elasticloadbalancing';
const loadBalancer = new LoadBalancer(this, 'elb-tcp-dict', {
vpc,
internetFacing: true,
healthCheck: {
port: 80,
},
listeners: [
{
externalPort:10000,
externalProtocol: LoadBalancingProtocol.TCP, // Sensitive
internalPort:10000
}]
});
loadBalancer.addListener({
externalPort:10001,
externalProtocol:LoadBalancingProtocol.TCP, // Sensitive
internalPort:10001
});
loadBalancer.addListener({
externalPort:10002,
externalProtocol:LoadBalancingProtocol.HTTP, // Sensitive
internalPort:10002
});
For aws-cdk-lib.aws-elasticache.CfnReplicationGroup:
import { CfnReplicationGroup } from 'aws-cdk-lib/aws-elasticache';
new CfnReplicationGroup(this, 'unencrypted-implicit', {
replicationGroupDescription: 'exampleDescription'
}); // Sensitive
new CfnReplicationGroup(this, 'unencrypted-explicit', {
replicationGroupDescription: 'exampleDescription',
transitEncryptionEnabled: false // Sensitive
});
For aws-cdk-lib.aws-kinesis.CfnStream:
import { CfnStream } from 'aws-cdk-lib/aws-kinesis';
new CfnStream(this, 'cfnstream-implicit-unencrytped', undefined); // Sensitive
new CfnStream(this, 'cfnstream-explicit-unencrytped', {
streamEncryption: undefined // Sensitive
});
For aws-cdk-lib.aws-kinesis.Stream:
import { Stream } from 'aws-cdk-lib/aws-kinesis';
new Stream(this, 'stream-explicit-unencrypted', {
encryption: StreamEncryption.UNENCRYPTED // Sensitive
});
Compliant Solution
url = "https://example.com";
url = "sftp://anonymous@example.com";
url = "ssh://anonymous@example.com";
For nodemailer one of the following options must be set:
const nodemailer = require("nodemailer");
let transporter = nodemailer.createTransport({
secure: true,
requireTLS: true,
port: 465,
secured: true
});
For ftp:
var Client = require('ftp');
var c = new Client();
c.connect({
'secure': true
});
For aws-cdk-lib.aws-elasticloadbalancingv2.ApplicationLoadBalancer:
import { ApplicationLoadBalancer } from 'aws-cdk-lib/aws-elasticloadbalancingv2';
const alb = new ApplicationLoadBalancer(this, 'ALB', {
vpc: vpc,
internetFacing: true
});
alb.addListener('listener-https-explicit', {
protocol: ApplicationProtocol.HTTPS,
port: 8080,
open: true,
certificates: [certificate]
});
alb.addListener('listener-https-implicit', {
port: 8080,
open: true,
certificates: [certificate]
});
For aws-cdk-lib.aws-elasticloadbalancingv2.ApplicationListener:
import { ApplicationListener } from 'aws-cdk-lib/aws-elasticloadbalancingv2';
new ApplicationListener(this, 'listener-https-explicit', {
loadBalancer: loadBalancer,
protocol: ApplicationProtocol.HTTPS,
port: 8080,
open: true,
certificates: [certificate]
});
For aws-cdk-lib.aws-elasticloadbalancingv2.NetworkLoadBalancer:
import { NetworkLoadBalancer } from 'aws-cdk-lib/aws-elasticloadbalancingv2';
const nlb = new NetworkLoadBalancer(this, 'nlb', {
vpc: vpc,
internetFacing: true
});
nlb.addListener('listener-tls-explicit', {
protocol: Protocol.TLS,
port: 1234,
certificates: [certificate]
});
nlb.addListener('listener-tls-implicit', {
port: 1234,
certificates: [certificate]
});
For aws-cdk-lib.aws-elasticloadbalancingv2.NetworkListener:
import { NetworkListener } from 'aws-cdk-lib/aws-elasticloadbalancingv2';
new NetworkListener(this, 'listener-tls-explicit', {
loadBalancer: loadBalancer,
protocol: Protocol.TLS,
port: 8080,
certificates: [certificate]
});
For aws-cdk-lib.aws-elasticloadbalancingv2.CfnListener:
import { CfnListener } from 'aws-cdk-lib/aws-elasticloadbalancingv2';
new CfnListener(this, 'listener-https', {
defaultActions: defaultActions,
loadBalancerArn: loadBalancerArn,
protocol: "HTTPS",
port: 80
certificates: [certificate]
});
new CfnListener(this, 'listener-tls', {
defaultActions: defaultActions,
loadBalancerArn: loadBalancerArn,
protocol: "TLS",
port: 80
certificates: [certificate]
});
For aws-cdk-lib.aws-elasticloadbalancing.CfnLoadBalancer:
import { CfnLoadBalancer } from 'aws-cdk-lib/aws-elasticloadbalancing';
new CfnLoadBalancer(this, 'elb-ssl', {
listeners: [{
instancePort: '1000',
loadBalancerPort: '1000',
protocol: 'ssl',
sslCertificateId: sslCertificateId
}]
});
new CfnLoadBalancer(this, 'elb-https', {
listeners: [{
instancePort: '1000',
loadBalancerPort: '1000',
protocol: 'https',
sslCertificateId: sslCertificateId
}]
});
For aws-cdk-lib.aws-elasticloadbalancing.LoadBalancer:
import { LoadBalancer, LoadBalancingProtocol } from 'aws-cdk-lib/aws-elasticloadbalancing';
const lb = new LoadBalancer(this, 'elb-ssl', {
vpc,
internetFacing: true,
healthCheck: {
port: 80,
},
listeners: [
{
externalPort:10000,
externalProtocol:LoadBalancingProtocol.SSL,
internalPort:10000
}]
});
lb.addListener({
externalPort:10001,
externalProtocol:LoadBalancingProtocol.SSL,
internalPort:10001
});
lb.addListener({
externalPort:10002,
externalProtocol:LoadBalancingProtocol.HTTPS,
internalPort:10002
});
For aws-cdk-lib.aws-elasticache.CfnReplicationGroup:
import { CfnReplicationGroup } from 'aws-cdk-lib/aws-elasticache';
new CfnReplicationGroup(this, 'encrypted-explicit', {
replicationGroupDescription: 'example',
transitEncryptionEnabled: true
});
For aws-cdk-lib.aws-kinesis.Stream:
import { Stream } from 'aws-cdk-lib/aws-kinesis';
new Stream(this, 'stream-implicit-encrypted');
new Stream(this, 'stream-explicit-encrypted-selfmanaged', {
encryption: StreamEncryption.KMS,
encryptionKey: encryptionKey,
});
new Stream(this, 'stream-explicit-encrypted-managed', {
encryption: StreamEncryption.MANAGED
});
For aws-cdk-lib.aws-kinesis.CfnStream:
import { CfnStream } from 'aws-cdk-lib/aws-kinesis';
new CfnStream(this, 'cfnstream-explicit-encrypted', {
streamEncryption: {
encryptionType: encryptionType,
keyId: encryptionKey.keyId,
}
});
Exceptions
No issue is reported for the following cases because they are not considered sensitive:
- Insecure protocol scheme followed by loopback addresses like 127.0.0.1 or
localhost.
See
Documentation
Articles & blog posts
Standards
