Hardcoding IP addresses is security-sensitive. It has led in the past to the following vulnerabilities:

Today’s services have an ever-changing architecture due to their scaling and redundancy needs. It is a mistake to think that a service will always have the same IP address. When it does change, the hardcoded IP will have to be modified too. This will have an impact on the product development, delivery, and deployment:

Last but not least it has an effect on application security. Attackers might be able to decompile the code and thereby discover a potentially sensitive address. They can perform a Denial of Service attack on the service, try to get access to the system, or try to spoof the IP address to bypass security checks. Such attacks can always be possible, but in the case of a hardcoded IP address solving the issue will take more time, which will increase an attack’s impact.

Ask Yourself Whether

The disclosed IP address is sensitive, e.g.:

There is a risk if you answered yes to any of these questions.

Recommended Secure Coding Practices

Don’t hard-code the IP address in the source code, instead make it configurable with environment variables, configuration files, or a similar approach. Alternatively, if confidentially is not required a domain name can be used since it allows to change the destination quickly without having to rebuild the software.

Sensitive Code Example

String ip = "192.168.12.42"; // Sensitive
Socket socket = new Socket(ip, 6667);

Compliant Solution

String ip = System.getenv("IP_ADDRESS"); // Compliant
Socket socket = new Socket(ip, 6667);

Exceptions

No issue is reported for the following cases because they are not considered sensitive:

See