HRDN-7222 - Permissions on installed compilers

(Hardening)

This information is provided as part of the Lynis community project. It is related to Lynis control HRDN-7222 and should be considered as-is and without guarantees. Any advice and commands should be tested before implementing them in production environments.

Description

Compilers turn source code into binary executable code. For a production system a compiler is usually not needed, unless package upgrades are performed by means of their source code. If a compiler is found, execution should be limited to authorized users only (e.g. root user).

How to solve

Compilers are used for translating source code into machine language. This process happens usually during the development cycle, or by package maintainers. Although many systems have a compiler installed, it is often not used. That is an unnecessary risk.

Evildoers might abuse the presence of a compiler to make their malicious attacks work. Due to protections in the Linux kernel, memory allocation and execution of processes, is limited. To circumvent these protections, a compiler on the related system is needed, so the attacker can determine specific memory locations and leverage a so-called exploit.

Hardening options

When possible, removal of any unneeded compilers is the best option. This prevents users from compiling source code into binary programs. This is unusual for a production server, as most software comes precompiled. If you still need the compilers on your system, consider changing the file permissions or file ownership. This way only the root, or other privileged users, can use the compiler.

Additional resources

Need more details?

Consider an upgrade to Lynis Enterprise to receive more guidance. The Enterprise version helps to you with daily health checks of your environment, learn in-depth system hardening, and resources to protect your systems better.

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