What is open source software?

Open source software (OSS) is software that is distributed with its source code, making it available for use, modification, and distribution with its original rights. Source code is the part of software that most computer users don’t ever see; it’s the code computer programmers manipulate to control how a program or application behaves. Programmers who have access to source code can change a program by adding to it, changing it, or fixing parts of it that aren’t working properly. OSS typically includes a license that allows programmers to modify the software to best fit their needs and control how the software can be distributed.

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What is the history of OSS?

The idea of making source code freely available originated in 1983 from an ideological movement informally founded by Richard Stallman, a programmer at MIT. Stallman believed that software should be accessible to programmers so they could modify it as they wished, with the goal of understanding it, learning about it, and improving it.i Stallman began releasing free code under his own license, called the GNU Public License. This new approach and ideology surrounding software creation took hold and eventually led to the formation of the Open Source Initiative in 1998.

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What is the Open Source Initiative?

The Open Source Initiative (OSI) was created to promote and protect open source software and communities.ii In short, the OSI acts as a central informational and governing repository of open source software. It provides rules and guidelines for how to use and interact with OSS, as well as providing code licensing information, support, definitions, and general community collaboration to help make the use and treatment of open source understandable and ethical.

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How does OSS work?

Open source code is usually stored in a public repository and shared publicly. Anyone can access the repository to use the code independently or contribute improvements to the design and functionality of the overall project.
OSS usually comes with a distribution license. This license includes terms that define how developers can use, study, modify, and most importantly, distribute the software.iii According to the Synopsys Black Duck® KnowledgeBase, five of the most popular licenses are:

• MIT License
• GNU General Public License (GPL) 2.0—this is more restrictive and requires that copies of modified code are made available for public use
• Apache License 2.0
• GNU General Public License (GPL) 3.0
• BSD License 2.0 (3-clause, New or Revised)—this is less restrictiveiv

When source code is changed, OSS must include what was altered as well as the methods involved. Depending on the license terms, the software resulting from these modifications may or may not be required to be made available for free

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What are some examples of OSS?

• GNU/Linux
• Mozilla Firefox
• VLC media player
• SugarCRM
• GIMP
• VNC
• Apache web server
• LibreOffice
• jQuery

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Is OSS bug-free?

The short answer is no. With multiple parties making modifications and improvements, it’s inevitable that open source software will contain quality, performance, and security flaws. However, the broad base of code contributors can also mean that bugs are identified and fixed faster.
No matter the type of software—open source or commercial—code flaws will exist. The main difference is who is responsible for fixing the bugs; for commercial software, vendors are responsible, whereas the consumer is responsible for open source software. With a robust set of AppSec tools and practices in place, OSS can be easily secured.

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