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:
- The developers will have to do a rapid fix every time this happens, instead of having an operation team change a configuration file.
- It forces the same address to be used in every environment (dev, sys, qa, prod).
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 at this address or spoof the IP address. Such an attack is always
possible, but in the case of a hardcoded IP address the fix will be much slower, which will increase an attack's impact.
Ask Yourself Whether
The disclosed IP address is sensitive, eg:
- Can give information to an attacker about the network topology.
- It's a personal (assigned to an identifiable person) IP address.
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.
Sensitive Code Example
let host = Host(address: "192.168.12.42")
let host = Host(address: configuration.ipAddress)
No issue is reported for the following cases because they are not considered sensitive:
- Loopback addresses 127.0.0.0/8 in CIDR notation (from 127.0.0.0 to 127.255.255.255)
- Broadcast address 255.255.255.255
- Non routable address 0.0.0.0
- Strings of the form
2.5.<number>.<number> as they often match
Object Identifiers (OID).