When running newer operating systems as Docker containers on older host systems—such as Ubuntu 20.04 or CentOS 7—a compatibility issue arises due to a new glibc call (clone3) not translating correctly to the older glibc (<=2.34) of the host system, resulting in the call being incorrectly translated, and blocked. One workaround to this issue involves…
This article is going to concentrate several SSH client related topics and optimisations I have implemented. Amongst are: SSH client modular configuration Initially, the configuration for SSH client should be present (per-user) in the user’s home directory, under .ssh/config. I believe that this configuration file is not modular enough, and when you want to add/edit/remove…
I got the following error message when attempting to upgrade RPM packages: Oracle Linux 8 introduced a bug with a package called rpm-plugin-selinux (details: rpm-plugin-selinux-4.14.3-28.0.1.el8_9) which prevents RPM packages from being installed correctly, either by dnf/yum or manually. The solution, as shown in this Oracle community forum is to downgrade the package rpm-plugin-selinux like that:…
This is a very technical and a limited solution to Cisco AnyConnect issue with unknown certificate on Linux (Ubuntu 22.04). AnyConnect version is 4.10. I hope this post will help others with a similar problem. The issue is around SAML authentication (an embedded web browser attempting to complete the authentication process), and its failure to…
Using custom mail aliases to run scripts is an existing practice. However, on modern Linux distributions it is blocked as a security risk. Following Postfix common guidelines do not allow for it to run the scripts. It reports the script as called, however – it does actually nothing. This has been verified on Oracle Linux…
GRUB2 password protection, secure Ubuntu boot loader, prevent unauthorised boot menu changes, enhance system security. In previous posts in this blog I have explained how to protect the system by disk encryption with a password retrial from the TPM. In another post, I have given some wider overview of system security and protection, but there…
