CIS Safeguard 2.6: Allowlist Authorized Libraries

CIS Safeguard 2.6: Allowlist Authorized Libraries

By Steve Gold
Posted in Security
On January 28, 2025

Written with contributions from Bryon Singh, Director of Security Operations, RailWorks Corporation

Safeguarding your software ecosystem is crucial, and ensuring only authorized libraries are used is like assembling a trusted team of superheroes. CIS Safeguard 2.6: Allowlist Authorized Libraries epitomizes the meticulous selection process of the Avengers’ roster in the Marvel Universe.

The Avengers' Assembly

Just as Nick Fury carefully selects each Avenger based on their abilities and trustworthiness, an allowlist ensures only vetted and trusted libraries are integrated into your software. This process prevents rogue code—much like preventing villains—from infiltrating your applications. By allowlisting authorized libraries, you're assembling a superhero team of reliable code components.

Selective Integration

The Avengers don't just let anyone join their ranks; each member must prove their worth. Similarly, before adding a library to your allowlist, it undergoes rigorous scrutiny to ensure it meets security and performance standards. This selective integration is vital to maintain a secure and efficient software environment.

Constant Monitoring

Even the Avengers need to adapt and grow. Similarly, your allowlist of libraries must be regularly updated to include new, trusted libraries while removing outdated or compromised ones. This continuous monitoring ensures that your software remains secure and up-to-date, much like the Avengers constantly upgrading their strategies and gear to tackle evolving threats.

CIS Safeguard 2.6: Allowlist Authorized Libraries involves limiting system access to only approved libraries, which can help prevent unauthorized or malicious code from executing. Here are some quick pros and cons:

Pros

  • Enhanced Security: Prevents unauthorized or malicious libraries from running, reducing the risk of code injection and supply chain attacks
  • Controlled Environment: Ensures only vetted, safe libraries are used, aligning with regulatory compliance and reducing vulnerabilities
  • Better Monitoring: Simplifies tracking of library use, making it easier to detect suspicious activity

Cons

  • Initial Setup Effort: Requires thorough initial inventory and setup, which can be time-consuming
  • Potential for Disruption: Legitimate applications may break if required libraries aren’t on the allowlist, impacting productivity
  • Ongoing Maintenance: Regular updates are needed to keep the allowlist accurate and effective, adding administrative overhead

Takeaway

Allowlisting libraries boosts security by restricting system access to safe code, but it requires diligent setup and maintenance to avoid workflow disruptions.

Resources

Here’s a link to the Software Asset Management Policy Template for CIS Control 2 provided free of charge from the fine folks at the Center for Internet Security:

Looking for even more detail? Here you go. If this still doesn’t satisfy your curiosity, DM me.

CIS Control 2 – Inventory and Control of Software Assets

Actively manage (inventory, track, and correct) all software (operating systems and applications) on the network so that only authorized software is installed and can execute, and that unauthorized and unmanaged software is found and prevented from installation or execution.

CIS Safeguard 2.6 - Allowlist Authorized Libraries

Use technical controls to ensure that only authorized software libraries, such as specific .dll, .ocx, and .so files, are allowed to load into a system process. Block unauthorized libraries from loading into a system process. Reassess bi-annually, or more frequently.

Steve Gold

Steve Gold

Steve Gold is the Cybersecurity Practice Director at Gotham Technology Group (Gotham). He is responsible for providing the vision and thought leadership to expand Gotham’s legacy of success and build a world-class cybersecurity practice. He works closely with Gotham’s customers, industry partners, and subject matter experts to develop relevant solutions for Gotham’s clients and prospects.

Prior to joining Gotham, Steve worked with the Center for Internet Security (CIS), where he expanded the global reach, revenue, and impact of the CIS Benchmarks, CIS Controls, and CIS Hardened Images. He led the efforts to promote the CIS portfolio of low-cost and no-cost cybersecurity products and services that help private and public organizations stay secure in the connected world. He grew a team of security specialists from 12 to over 40 to assist organizations with implementing security best practices in their continual journey of cybersecurity maturity.

During his more than 20-year career, Steve led teams responsible for developing and implementing technology solutions at some of the industry’s most recognized companies such as Varonis, VMware, Dell & Wyse Technology

Steve is a frequent speaker/moderator at industry conferences and webinars, covering a wide array of information security topics. He resides and works remotely in Baltimore, MD.