Category: IT Security

In the past, when connecting to EC2 instances in a Private Subnet on AWS, it was common to set up a Bastion Host or Jump Server. Administrators would first connect to a Bastion EC2 in a Public Subnet via SSH/RDP, and then connect to the server in the Private Subnet. However, in recent AWS environments,…

On June 13, 2026, a web service that was in operation suddenly became inaccessible. At first, it seemed like a simple server reboot issue. However, it was actually a rather deep network outage involving a Linux kernel update and the Cilium eBPF data path. The interesting point is that this outage was not analyzed by…

A document recently published on GitHub, claimed to be the system prompt for Claude Fable 5, has garnered significant attention in the AI community. This document is not merely a brief guideline on “how the AI should respond,” but rather a comprehensive operational manual detailing how Claude should handle product information, safety policies, search, file…

When people think of firewalls in AWS, many first recall Security Groups or AWS WAF. However, Security Groups are closer to resource-level access control, and AWS WAF is a web application firewall that inspects web requests. In this article, we will exclude AWS WAF, which is a web application firewall, and focus on AWS Network…

Amazon ECS security checks can mostly be summarized as: “How much can a container infringe on host privileges?”, “Is it directly exposed to the external internet?”, and “Are sensitive information and logs handled securely?”. In particular, the ECS Task Definition is a critical security point that includes container execution methods, permissions, file systems, environment variables,…

When operating AWS EC2, you often encounter the terms IMDSv1 and IMDSv2. IMDS stands for Instance Metadata Service, a service that allows an EC2 instance to query its own metadata from within the instance. For example, inside an EC2 instance, you can query the following information: Instance ID AMI ID Region Availability Zone Network information…

Anthropic’s Top Public Model Aimed at Long-Term Autonomous Tasks The competition among AI models is increasingly shifting from “short answers” to “agents that work autonomously for extended periods.” In this trend, Anthropic has unveiled Claude Fable 5. Anthropic describes Fable 5 as “the most powerful Claude model released to the general public,” stating that it…

When operating EC2, there are repetitive tasks. These tasks include installing operating systems, applying security patches, installing agents, configuring logs, reflecting company standard security settings, and then creating and distributing AMIs. While this can be done manually on a small scale, as accounts, regions, and operating environments grow, image management itself becomes an operational burden.…

Hello! This is the fourth installment of our GitOps series. Today, we’re going to delve deep into the ‘Reconciliation Model,’ a core mechanism of GitOps operations and a topic many engineers ponder. Shall we master the differences between the Pull method and the Push method, the first choices you encounter when implementing GitOps, in just…