• Posted by: Eng. Donya Bino
• February 05, 2026

Why Free & Open-Source Software Is a Prime Exploit Target

Free and open-source software (FOSS) powers most of the internet, mobile devices, servers, cloud infrastructure, IoT products, and even many proprietary applications. It is fast, flexible, community-driven, and usually free of licensing costs, which is exactly why it has become one of the most attractive targets for attackers in recent years.

Here are the main structural reasons free software is disproportionately exploited, together with real patterns and practical implications:
1. Extensive Attack Surface Area and Widespread Utilization
a) Some of the most popular open source libraries in use today are OpenSSL, Log4j, XZ Utils, Apache Struts, Spring Framework and Redis which are utilized by millions or billions around the world on an ongoing basis.
b) If a vulnerability is discovered in an open source library that is widely deployed, the number of organizations affected could be in the hundreds of thousands within a very short period of time (supply chain attack multiplier).

An example of this is the Log4Shell vulnerability (CVE-2021-44228) in Log4j 2, which affected many types of Java-based applications (e.g., Minecraft servers, enterprise applications and cloud services). A single exploit chain allowed remote code execution, attackers scanned the entire IPv4 space in hours and compromised tens of thousands of systems within days.

2. There Are A Large Number Of Invisible Dependencies Within Software (e.g., A High Number Of Transitive Dependencies)
a) Modern Software Contains Many (At Least Ten) Transitive Dependencies (I.e., Libraries With Their Own Transitive Libraries)
b) Developers Will Rarely Perform An Audit To Determine The Auditability Of Their Indirect Libraries → Thus, An Attacker Will Only Need To Compromise One Library In The Chain

Example: The XZ-Utils Backdoor, Also Known As "XZ-LZMA" (2024), There Is An Entire Ecosystem Of Software That Is Relying On The LibLZMA Compression Library As It's Base For Another Layer Of Software. When liblzma was discovered to have an undisclosed backdoor buried within it by a single maintainer (who was under tons of social engineering pressure), it was discovered just before any widespread use, but if it had not been found earlier, the backdoor could have been used against SSH access to nearly all servers running Linux globally.

3. Burnout of Maintainers and the Existence of Single Points of Failure 
a) A large percentage of critical parts from open source projects are maintained by either single individuals, very few individuals, or volunteers with little to no financial support. 
b) Burnout, a lack of code reviews, rushed merges, and social engineering attacks against maintainers create exploitable opportunities. 

Real pattern of exploitation: Beginning in 2024 and continuing into 2025, numerous incidents of successful compromisation started with targeted harassment and befriending of single maintainers → exploitation by injection of minor malicious code during periods of fatigue or established trust.

4. Reduced Threshold for Contributions → Increased Opportunities to Insert Malicious Code
a) Open contribution systems may provide added value, but can also lead to unwanted consequences.
b) Malicious users have submitted helpful, for example fixes to typos, editing or ok to add a small increase in speed. They also add potential back doors.

For example; a number of developers have used the packages on npm, PyPI or ruby-tools being the victorious as "friend" contributors to sap certain credentials or mine content on other systems.

5. Lack of Software Bills of Materials (SBOM) and Existence Checks
a) Few open source projects will publish a verifiable SBOM or cryptographically verify each release commit.
b) Attackers can more easily replace legitimate packages in mirrors or insert typosquatted versions.

Real pattern: “Dependency confusion” attacks (2021–ongoing) exploit private package name collisions → attackers publish malicious versions on public repositories that internal build systems pull instead of the intended private package.

Practical Implications & Protection Steps 
For individuals / home users
1. Use the Google Play Store, Microsoft Store or trusted mirrors to access Operating Systems and applications.
2. Avoid cracked and pirated software because they contain stealers or droppers inside them.
3. Use Dependency-Check, Trivy or other tools to scan your own projects or your own Docker images.
4. Make sure that auto-updates are enabled for your operating system, browsers and applications.

For organizations / developers
1. Generate and validate SBOMs for every build you make in CycloneDX and SPDX format;
2. Pin and verify the hashes of all dependencies in your build pipelines.
3. Sign your code and repository with a code and repository-signing service such as Sigstore or Cosign. 
4. Use automated SCA tools such as Dependabot, Snyk Open Source or OWASP Dependency-Check to perform SCA on your software.
5. Limit trust for transitive dependencies by reviewing and vendor vetting them for critical libraries before using.
6. Contribute funds and/or time to critical Open Source projects upon which your organization is reliant.

Key Takeaways
Free and open-source software is not inherently insecure, it is inherently widely deployed, which makes even a single vulnerability extremely valuable to attackers. The same transparency and collaboration that make open source powerful also create opportunities for supply-chain compromise, maintainer burnout exploitation, and dependency confusion.

The lesson is not to abandon open source, it is to secure the supply chain the way we secure our own code: verify provenance, reduce blast radius, enforce least privilege, and actively support the maintainers who keep the ecosystem alive.