is only done until a point of time at which the software becomes unsupported, usually referred to as end-of-life. Particularly in a quasiembedded solution like an O-RAN RU, this is an aspect that is often overlooked. We discussed Linux LTS and RYO versus commercial grade solutions before (Sections 1.3 and 1.4 respectively). SSH is the standard service used to manage a server remotely. Therefore it must be configured securely. 210 Open Radio Access Network (O-RAN) Systems Architecture and Design Software often provides standard accounts at installation time. Also, account names like 'admin' or 'guest' are widely used. These accounts are an easy target for attackers, and are therefore best deleted or renamed, or at least provided with a strong password. Server software often is installed with demonstration or test scripts are used to test if the software is functioning as expected. When the software is deployed, such components should be disabled because they often provide unneeded information which may be used by an attacker. Such components are usually poorly secured. Detailed error information (logs sent over the network to debug any issues) may aid an attacker getting a full view on a target host's configuration and application code. Error information therefore should be transmitted through a secure link and not contain unnecessary technical information. Beyond keeping the os updates, it is important that the platform keeps all components updated. Having a Bill Of Material (BOM) of all components included in the system and knowing what their Common Vulnerabilities and Exposures (CVE) status is with MITRE (the MITRE Corporation is a non-profit organization managing R&D for cyber security and similar fields) is crucial. Having a development/test/release process flow that keeps security central will reduce the friction needed to ensure security. Application architecture The security of custom software is largely dependent on the application architecture. The correct use of a modern framework and software technique