Need

Prevention of sensitive information exposure through print functions

Context

• Usage of Go 1.16 for building efficient and scalable applications
• Usage of gin-gonic/gin for building web applications in Go

Description

Non compliant code

        package main

import (
	"github.com/gin-gonic/gin"
)

func main() {
	r := gin.Default()

	r.GET("/test", func(c *gin.Context) {
		// Vulnerable code
		println("This is a test message. It may contain sensitive information.")
		c.String(200, "Hello, World!")
	})

	r.Run()
}
        
        

The above Go code uses the Gin web framework to create a simple web server with one route, /test. The vulnerability lies in the use of the println function. This function prints a message to the standard output (stdout), which is typically the terminal or console from which the application is run.

In a development environment, using println or similar functions can be helpful for debugging and understanding the flow of the program. However, in a production environment, such print functions can expose sensitive information. This is because the output of these functions is often logged and these logs can be accessed by unauthorized individuals.

In the above code, although the printed message ("This is a test message. It may contain sensitive information.") is not sensitive, it represents a scenario where sensitive information such as user data, system details, or error information could be printed.

This constitutes a technical information leak, as it potentially allows unauthorized individuals to gain insights into the inner workings of the application, which they could use for malicious purposes.

Steps

• Remove or comment out any print functions that output sensitive information.
• Review the codebase for any other instances of print functions and remove them as well.
• Consider using a logging framework instead of print functions to handle debugging and error messages.
• Ensure that the application is not running in a development environment when deployed to production.
• Regularly review and update the codebase to remove any potential instances of print functions.

Compliant code

        package main

import (
	"github.com/gin-gonic/gin"
)

func main() {
	r := gin.Default()

	r.GET("/test", func(c *gin.Context) {
		// Removed the print function to prevent information leak
		// println("This is a test message. It may contain sensitive information.")
		c.String(200, "Hello, World!")
	})

	r.Run()
}
        
        

The original code contained a print function that outputted a test message. This is a potential security vulnerability as it could leak sensitive information. This is especially dangerous in a production environment where this information could be accessed by malicious actors.

The fixed code removes this print function, preventing the potential information leak. It's important to note that this is just one instance and the entire codebase should be reviewed for any other instances of print functions.

In addition, it's recommended to use a logging framework for handling debugging and error messages. This allows for better control over what information is outputted and can be configured to output nothing in a production environment.

Finally, it's crucial to ensure that the application is not running in a development environment when deployed to production. This can be done by setting environment variables or using a configuration file.

Regular code reviews and updates are also necessary to ensure that no new instances of print functions are introduced that could potentially leak sensitive information.

References

• 237. Technical information leak - Print Functions