The Best Practices Cheat Sheet for Secure Coding in Python

Programming is at its peak at the moment with Python leading the pack with the! It is very popular because of its simple use and effectiveness in automation and DevOps. However, because of the nature of apps and services this programming language handles it is VERY important to have the code secured. You can achieve this by following the 11 best Python secure coding practices we developed in a cheat sheet for you and your teams.

Why Secure Coding is Important

The developers need to be vigilant and keep in mind:

  • Security and safety of code.
  • Optimization and efficiency of code.
  • Application architecture and design requirements.

The Risks Involved with not writing secure code

If your application is not secured to the fullest then it makes a gateway for the security thefts to come in. Like this they have direct control of the particular device or provide access path to another device.

  • Results

This might result in the following:

  • Service loss.
  • Loss of life.
  • Compromised secrets.
  • System damage.
  • Denial of service to single user.

Why Follow Secure Coding Standards

Why follow coding standard

Developers and programmers can easily weed out common vulnerabilities in their software, for this all they need to do is follow some great practices and guidelines which are known as secure coding standards.

They bring good in the 4 following ways:

  1. It removes all the commonly exploited vulnerabilities present in software.
  2. Prevents cyberattacks.
  3. Sensitive information is not leaked out.
  4. Helps save up cost which may occur in case of an exploit.

2 Common Code Security vulnerabilities that are found

Python Security Vulnerabilities

Buffer Overflow:

Today through IoT the embedded systems are becoming connected with the world outside. This creates new ways and more opportunities for malicious code attacks.

Buffer Flow, through this the security theft is able to put code or data there in the system. If all happens correctly then that particular system is opened to further instructions.

Code Injection:

Now this is another one which exploits a bug which is occurred by processing data which is not valid. This is a kind of injection attack which we can defend.

Shell-lock, in this arbitrary code can be executed there on remote system in order to perform malicious activities.

11 Best Secure Coding Practices for Python Coding (A Cheat Sheet to Secure Python Code)

For best coding you need to keep in mind regarding some things, we have compiled for you a list, follow through to know more:

Validate the inputs

Data sources which you do not trust make sure to know them as like this there would be fewer chances of software vulnerabilities. Keep an eye on external data sources which include:

  • Network interfaces.
  • Environmental variables.
  • User-controlled files.

Authentication and Management of Passcode

Just limiting access to users like this you can prevent cyber-attacks and data breaches. You can use one of the following ways as well:

  1. For password, hashing use a trusted system.
  2. Use of multi-factor authentication.
  3. Authentication credentials are strong.
  4. Making sure to have good password strength.
  5. Meet up with complexity requirements.

Use Python’s Recent Version

It is always best to keep your system and all the apps and software you use up to date. Its version 2.7 which came out in 2020 will lose its support therefore you need to move up the ladder and grab Python 3.

If you continue with the older version then it will become difficult to update it in the future. You should also keep your IDE updated all the time as a vulnerability can also appear in the actual tooling. We also advise using free and open-source IDEs as they tend to be more secure and always kept updated by the community.

Access Control is a must

This goes hand in hand with authentication to be sure that any security theft cannot have easy access to the system.

Default Deny is safe

We suggest you adopt this, now if you are not aware of the term then don’t worry as it states that all those who can’t demonstrate authorization should not be given access.

Complexity can cause problems

Simple code ensures security. If the design is complex then there are chances that vulnerabilities would make their way in.

Cryptographic is the future

Values generated randomly need to be generated through an improved random number generator so that they can’t be guessed.

Fast Error Handling

Code written down in the best way can also have errors, what needs to be done is we treat errors at their earliest.

Protect from SQL Injection 

If you do not know then let us open your ears by telling you that SQL injections are also capable of dropping sensitive data from insecure devices. Make sure to take this one seriously as well and follow all the procedures to protect your database.

ALSO SEE: A guide to Install Python 3 Securely on Windows.

Data Protection is key

What security thefts aim is to get their hands on sensitive data and have access to it? Protect your data in the best possible way, we have also listed some ways for you:

  1. Have know-how of all the code elements.
  2. Make sure to regularly delete cached copies of sensitive data present on the server.
  3. Ensure you don’t have any stored passcodes and connection strings in clear text or another non-encrypted manner on side of the client.

Model your threats

It is used to identify threads and then provides solutions. Make sure to do this on regular basis. Make sure not to Commit anything with a Passcode.

If we assume that developers using Github, then please make sure you have not left any password in any file, readme and description of URL. If yes, remember that it shall be there in data and accessed by anyone.

Get Bandit Installed

For every project, we recommend that you install a bandit which is used to scan the code for known vulnerabilities like issues with YAML.

Why you should consider Bandit:

  1. It ranks the risk of security from low to high.
  2. Informs users regarding which lines of code are causing the issues.
Paul@ninja-ide:~# Pip install bandit

Use Procedure

It scans all the python files which have been selected and after that presents report in the form of an abstract syntax tree.


  • Very quick.
  • Easy to use.

7 common coding mistakes done by developers you should avoid

Common Secure Coding Mistakes

  1. Having trust on third-party code.
  2. Hard-coding backdoor accounts.
  3. SQL injections not verified
  4. Remote file inclusions.
  5. Handing insecure data.
  6. Not able to encrypt data.
  7. Using a non-secure cryptographic system.


Secure coding is the way to go because you must start at the core of an application or software to be safe. Most data breaches happen and come to light years after because of 0-day vulnerabilities or bugs discovered in code that developers or companies don’t even know. This is why you need to start getting your development teams to implement secure coding standards throughout to start in a safe manner. You can also look at OWASP’s best practice guide for further tips.


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