Technology
AI Deleted a Production Database in 9 Seconds
I examine the potential dangers of AI agents in production environments through a real data loss scenario. Why should we be careful?
#security
124 posts found.
Career
Dependency Vulnerability Pattern: Management Status in Small Projects
I examine the challenges of dependency vulnerability management in small projects, the patterns I've encountered, and my pragmatic solution approaches.
Tutorials
JWT Lifecycle vs. Secret Rotation: Which is More Secure?
Comparing JWT lifespans and secret rotation strategies, I'll share my experiences on which is more secure and practical in real-world scenarios.
Life
Practical Approach to Kernel CVE Emergencies
My personal experiences and lessons learned on practical methods, rapid response, and risk management strategies I apply when encountering Kernel CVEs.
Career
The Principle of Least Privilege: Operational Speed's Security Cost
An in-depth analysis of the principle of least privilege's impact on operational speed, security risks, and practical applications.
Tutorials
JWT Revocation: Stateless Promise Meets Real-World Challenge
While JWT's stateless nature sounds appealing, I explore the challenges of token revocation in real-world scenarios and my solution approaches.
Technology
Secret Rotation: Practical Ways to Enhance Security
Regularly rotating secrets in systems is a critical security step. Drawing from my own experiences, I'll discuss secret rotation strategies and practical...
Technology
Zero-Trust Architecture: A Pragmatic Roadmap for Small Teams
A step-by-step guide on how small teams can practically and effectively implement zero-trust architecture. Core principles, tools...
Technology
Switch Hardening: Always a Necessary Step?
We delve deep into switch hardening, a cornerstone of network security. When is it necessary, what are the trade-offs, and its practical applications.
Life
Why VLAN Segmentation is No Longer as Necessary? (Or Is It?)
With 20 years of system and network experience, I examine why VLAN segmentation is no longer as essential as it used to be, in a practical and direct manner...
Life
Kernel CVE Response: Quick Patch or Defense in Depth?
Drawing on years of experience, this post explores whether to simply patch or strengthen a system with layered defense when a Kernel CVE emerges…
Tutorials
AI Prompt Injection Defense: Building Effective Strategies in 5 Steps
Develop actionable and effective strategies in 5 steps to protect Large Language Models (LLMs) from Prompt Injection attacks. Practical solutions based on my.
Technology
The Operational Cost of JWT Lifecycle Management: Overlooked Details
I delve into the operational burden and cost of JWT lifecycle management, examining overlooked strategic points and practical solutions.
Life
Secret Rotation Automation: The Operational Cost of Security
I analyze the operational overhead of secret key rotation and the cost-effectiveness of automation. Real-world scenarios and trade-offs.
Technology
Why is VLAN Segmentation Overhyped in Small Networks?
I share my experiences on the administrative burden, performance losses, and practical alternatives of VLAN segmentation in small-scale networks.
Tutorials
Multi-Tenant ERP: The Risks of a Shared Schema
An in-depth look at why the shared schema approach in multi-tenant ERP systems is risky, complete with real-world examples and technical details.
Career
The Cost of Kernel CVE Patching Frequency in SLA Commitments
How often should you patch kernel CVEs while meeting your SLA commitments? I took a deep dive into the costs and risks involved.
Tutorials
JWT Refresh and Revocation Mechanisms: The State of Security Practices
I'm sharing my experiences on the role of JWT (JSON Web Token) refresh and revocation processes in security practices and their implementation strategies.
Career
Three Challenging Aspects of the Kernel CVE Patching Process: My
I examine three critical challenges in the Linux kernel CVE patching process, with concrete examples and practical solutions.
Technology
Why is Network Switch Hardening Often Neglected?
I examine why network switch hardening is often overlooked, drawing from my real-world field experience. Closing security vulnerabilities...
Career
Modern Approaches to Secret Rotation: Securing Your Systems
Learn modern secret rotation practices to keep your systems secure. In this guide, we will walk through the process step-by-step.
Life
Dependency Vulnerabilities in CI/CD: 3 Practical Management Methods
Learn 3 effective methods for managing dependency vulnerabilities in your software development processes with Mustafa Erbay's experience. Enhance CI/CD.
Technology
VLAN Segmentation: Balancing Security and Performance
I explain how I strike a balance between performance and security when moving from a flat network to VLAN segmentation, sharing technical details from my field.
Tutorials
Restricting Tool Usage in AI Agents: Secure Design in 3 Steps
How do you control the tool usage of AI agents? Secure agent architecture with schema hardening, isolation, and RBAC.
Life
Secret Rotation: 3 Core Principles for Secure Applications
Exploring secret rotation, a cornerstone of application security, and delving into my own principles of automation, lifecycle management, and seamless.
Life
Kernel CVE Response: The Unexpected Bill of Delaying
We examine why delaying responses to kernel security vulnerabilities can be costly with concrete examples. Read to understand the price of procrastination.
Career
Security Patching on My Own VPS: Hours Stolen from a Client Project
I explain step-by-step a security vulnerability encountered during a client project and how I patched it on my own VPS. Lessons from field experience.
Technology
Three Wrong AD Tier Model Assumptions: 8 Months in the Field
Microsoft tier model (T0/T1/T2): three assumptions debunked during 8 months of field transition. Lessons learned the hard way.
Tutorials
The Invisible Wars of Environment Variable Management: Hidden…
Discover why environment variable management is so critical, the common nightmares, and effective strategies to win these hidden wars. From application...
Technology
Vault Unlocked: The Hidden Secret in the Environment Variable
Environment Variables play a vital role in application configuration. But mismanaging them can leak hidden secrets and…
Career
Hidden Sentinel Wars in Production: A Firewall Betrayal
Dig deep into the unexpected effects of Sentinel-based firewalls in production and these 'hidden wars.' Strategies and solutions.
Technology
The Silent Betrayal of Reverse Proxy Buffer Settings
Discover the hidden impact of reverse proxy buffer settings on performance and security. Optimization tips and tricks on the Mustafa Erbay blog!
Career
Managing a Security Vulnerability: A Leader's Hair Shirt
Learn the challenges and strategies of managing security vulnerabilities effectively as a leader. Use this guide to turn crises into opportunities.
Technology
Feature Flags and Configuration Governance: Parameter Store and Audit
Treating configuration like a product: feature flags, parameter store, schema, approval flow, audit log, and rollback discipline.
Technology
Kubernetes Network Policies: Invisible Walls Between Pods
Learn how to secure network traffic between pods using Kubernetes Network Policies. A from-A-to-Z guide with detailed examples for Network…
Technology
Secure B2B File Flow with an Object Storage Dropzone
An approach to building secure B2B file exchange using an object storage dropzone, short-lived access, and audit trails — instead of an SFTP bottleneck.
Technology
Certificate Expiry Nightmare: The Hidden Traps of Auto-Renewal
Explore the hidden traps and possible failure modes inside the auto-renewal process of certificates that are vital to digital security. Don't let your security…
Tutorials
Session Recording on the Bastion: tlog + sudo I/O + SSH Audit Pipeline
Making privileged access visible on the bastion: tlog/sudo I/O logging, the access model and a SIEM pipeline.
Technology
Syslog on Network Devices: TLS, Buffering, and Log Storm
A model for turning syslog loss and log storm risk into a reliable log channel for incident/audit, using TLS/relay, disk-backed queue, and rate limiting.
Technology
Protecting Router & Switch Control Plane with CoPP/CPP…
A CoPP/CPP model that classifies and polices routing, management, and ICMP traffic on the router/switch control plane to reduce CPU exhaustion and adjacency…
Tutorials
Defense Strategies Against Kubernetes DNS Cache Poisoning
Learn effective defense strategies against DNS cache poisoning attacks in Kubernetes environments. Discover methods to strengthen your security.
Tutorials
Core Dump Management and Privacy Runbook with systemd-coredump
Collecting core dumps in production: limits, retention, encryption, access and a practical runbook for safe analysis during an incident.
Tutorials
Kubernetes API Server Audit Log: Policy and SIEM Pipeline
Collecting Kubernetes audit logs without drowning in noise: a practical approach to policy, retention, masking and SIEM correlation.
Tutorials
Centralized Logging with systemd-journal-remote: mTLS and Retention
A practical setup and runbook for shipping journald logs over mTLS to a central collector — without adding agents — while running a disciplined disk budget…
Career
Access Review and Privileged-Access Cadence in Operational Leadership
Moving privileged access past the 'who has it?' question into a working governance discipline built on JIT, break-glass, audit, and revocation.
Technology
Preventing Edge Outages with BGP Max-Prefix Limits
Designing, monitoring, and writing an incident runbook for the max-prefix guardrail that protects edge routers during route leaks and bad-prefix waves.
Technology
DDoS Scrubbing Center Design: GRE, BGP, and Failover
GRE tunnels, BGP signaling, capacity, and an operational runbook to keep the service up by diverting traffic to scrubbing during an attack.
Technology
Enterprise DNS Firewall with DNS RPZ: Threat Blocking and Operations
Build a sustainable DNS security control by blocking threat domains via RPZ at the recursive resolver, with proper exception handling and observability.
Technology
Enterprise SSO Federation: A SAML/OIDC Gateway Architecture
An SSO broker design that unifies legacy SAML applications and modern OIDC services under a single identity policy — secure and operationally manageable.
Technology
MTU and PMTUD Blackhole: An Incident Runbook
When some users work and others don't, a frequent cause is broken PMTUD and an MTU blackhole. Diagnosis steps and a permanent fix.
Technology
Self-Hosted CI Runner Security: Isolation, OIDC and Secrets
A practical model that lowers supply-chain risk on self-hosted CI runners with isolation, network boundaries and OIDC-based short-lived authorization.
Technology
Egress Control in ZTNA: Designing Against Data Exfiltration
ZTNA isn't just about inbound access. A practical approach to data leakage with egress (outbound) control, DLP signals and service-centric segmentation.
Tutorials
Kubernetes Control Plane Certificate Expiry: A Runbook
When API Server access suddenly breaks with x509 errors; certificate renewal and safe recovery steps for kubeadm-based clusters.
Tutorials
Golden Image Pipeline with Packer: CIS Baseline and Patch Strategy
A golden image approach that hardens and tests the server image at build-time, accelerating patch, drift and emergency CVE workflows.
Tutorials
Packet Capture in Production with tcpdump: A Runbook
Practical tcpdump techniques for collecting minimal-yet-sufficient packet evidence during incidents: filters, snaplen, ring buffer, privacy, and handover…
Tutorials
Terraform CI Guardrails: Plan/Apply, Drift, and Policy Check
Balancing safety and speed in IaC: a guide to managing prod changes through plan/apply separation, drift detection, policy-as-code, and approval flows.
Tutorials
Centralized Logging with Windows Event Forwarding (WEF)
Subscriptions, health checks, and a triage runbook to centrally collect and validate security and operations signals in Windows domain environments using WEF.
Tutorials
Local Admin Password Rotation with Windows LAPS (AD/Entra)
Cut down lateral movement risk by automatically rotating local admin passwords across servers and clients; build secure operations on top of delegation and…
Technology
Firewall Rulebase Cleanup: Waves with Hitcount and Shadow Rules
Pull your firewall rule set out of the 'don't touch it, it'll explode' state with hitcount, log evidence, ownership, and a wave-based approach to safely…
Technology
Segmentation and Governance with Transit Gateway in Hybrid Cloud
A practical architecture guide that handles hub-spoke and Transit Gateway design together with security, route control, and operational observability.
Technology
Time Synchronization in Critical Systems: NTP, PTP and Observability
An architectural, security-focused, and operational view of NTP/PTP for distributed systems where TLS, log correlation, and consistency depend on accurate time.
Technology
Kubernetes Etcd Encryption at Rest + KMS Design
Protecting Secrets with real cryptography rather than just base64: encryption configuration, KMS integration, and an operational rotation model.
Technology
From Pilot to Production: 802.1X (NAC) in Enterprise Networks
A field-tested approach to taking 802.1X from pilot to production: identity, policy, exceptions, and the runbook that turns it into a living control plane.
Technology
L2 Encryption with MACsec in Enterprise Networks
Hardening campus and data center backbones by encrypting L2 links with MACsec (802.1AE): design choices, risks, and operations.
Technology
Kernel Live Patching and a Maintenance Model on Enterprise Linux
Managing kernel security patches without reboot pressure: a live-patch approach, the risks, a ring strategy, and operational discipline.
Technology
QUIC / HTTP/3: Security and Operations on Enterprise Networks
A practical approach to managing HTTP/3 traffic over UDP/443 without breaking security, visibility, or performance.
Technology
Trust Boundary at the SD-WAN Edge: Egress Policy, DNS, and Logging
Preserving the trust boundary across DIA / DC / cloud egress in SD-WAN: traffic classification, DNS strategy, split-tunnel, and a centralized log model.
Tutorials
An NTS and NTP Hardening Runbook with chrony
A practical chrony runbook for enterprise servers covering secure NTP (NTS), access restrictions, verification commands, and alarm thresholds.
Tutorials
Server Inventory and Security Signals with FleetDM + osquery
Turn 'what's on which server?' into a living inventory; a guide for scaling osquery queries with FleetDM into operational and security signal.
Tutorials
A Safe Migration Runbook from iptables to nftables
Reduce risk while moving production firewall rule sets from iptables to nftables using observability, wave-based rollout, and fast rollback.
Tutorials
Phased Hardening of Kubernetes with PSA + Kyverno
Roll out security guardrails in production clusters gradually with Pod Security Admission (PSA) and Kyverno: an audit→warn→enforce plan.
Tutorials
Kubernetes RBAC: Least Privilege + Break-Glass Model
A practical RBAC framework for role design, identity integration, and time-boxed emergency access (break-glass) without depending on cluster-admin.
Tutorials
A WORM Backup Layer Runbook with S3 Object Lock
Practical steps for building a WORM (Write Once Read Many) layer against ransomware and accidental deletion using S3 Object Lock, retention policies, and…
Tutorials
GitOps Secrets Management with SOPS + age
A practical SOPS + age setup and operational discipline for keeping encrypted secrets in Git and decrypting them safely inside CI/CD and the cluster.
Tutorials
AAA on Network Devices with TACACS+: Command Authorization and Audit
A TACACS+ approach that reduces local admin sprawl on network devices and turns session traces into proof through roles, command authorization, and accounting.
Tutorials
A Pre-Validation Pipeline for Network Changes with Batfish
A practical Batfish flow that validates routing/ACL changes before they reach production via 'snapshot + question set,' catching human error early.
Tutorials
Kubernetes Admission Webhook Timeouts: A Runbook for Frozen Deploys
Field runbook to rapidly triage hung deploys caused by Validating/Mutating webhook latency and apply a risk-controlled mitigation.
Tutorials
Workload Identity and mTLS with SPIFFE/SPIRE
A guide to wiring service-to-service mTLS through SPIFFE identities and SPIRE-issued short-lived certificates instead of relying on IPs and static secrets.
Tutorials
SSH + FIDO2: Phishing-Resistant Admin Access (Practical Runbook)
Hardening admin access with OpenSSH security keys (ed25519-sk) using PIN + touch confirmation, while keeping break-glass scenarios intact.
Technology
Secure Boot + TPM: A Root of Trust for Server Infrastructure
A practical model for making the trust chain from firmware to kernel measurable, without locking operations down in the process.
Tutorials
Protecting the Kubernetes Control Plane with API Priority and Fairness
A practical APF setup that prioritizes critical traffic and fairly queues noisy callers, lowering the risk of API server overload.
Tutorials
Short-Lived SSH Certificates with an OpenSSH CA
An OpenSSH CA-based approach to set up auditable, time-bound SSH access in place of shared bastion accounts and long-lived keys.
Tutorials
Hardening Services with systemd Sandboxing (ProtectSystem…
Constrain services into a tighter permission set without changing the application itself: filesystem, capability, syscall, and network limits.
Career
Evidence Collection Kit and Roles During an Incident
An evidence set, time standard, role assignment, and practical checklist to break the panic-driven 'SSH into one server' reflex.
Technology
DDoS Response Runbook with BGP RTBH and FlowSpec
A controlled approach to reducing DDoS impact during operations using an RTBH/FlowSpec decision tree, verification steps, and a rollback plan.
Tutorials
Enterprise NTP Architecture with Chrony, and Drift Alerting
Chrony settings, firewall recommendations, and drift/loss alarms to design a hierarchical and secure time synchronization.
Tutorials
Operational Runbook for JWKS Key Rotation
A runbook to triage the 401 wave (kid mismatch/JWKS cache) that occurs during JWT key rotation, and to set up safe overlap/caching strategy.
Tutorials
Privileged Command Monitoring Runbook on Linux with Auditd
A practical approach that makes privileged operations observable and auditable in production using sudo, auditd rules, and log forwarding.
Tutorials
Linux TCP Backlog and SYN Flood Resilience Runbook
A runbook to triage the connect timeout crisis when the SYN backlog/accept queue fills up, apply rapid mitigation, and design lasting resilience.
Tutorials
High Availability and Split-Brain Runbook with Redis Sentinel
A field-ready runbook for operationally managing quorum, failover, and split-brain risk in a Redis Sentinel-based HA setup.
Technology
Maintenance Wave Architecture for Patch Orchestration on…
An architectural decision frame for rolling out patches across large platform fleets in controlled waves rather than in a single pass.
Tutorials
Sensitive-Data Masking Pipeline for Logs with Vector and VRL
A practical Vector and VRL based approach for cleaning sensitive fields out of a centralised log stream before they reach the destination.
Technology
A Dedicated DNSSEC-Validating Resolver Layer in Enterprise Networks
An enterprise architecture approach that places DNSSEC validation in a dedicated resolver layer to raise trust in name resolution.
Technology
A Digital Twin Layer for Policy Drift in Enterprise Networks
A digital twin approach for seeing drift in firewall, routing, and segmentation rules without touching production.
Technology
RPKI-Based BGP Trust Chain in Enterprise Networks
An architectural approach to building an RPKI-based trust chain in enterprise networks to reduce BGP route leak and forged origin risks.
Technology
Break-Glass Access Vault Architecture in Enterprise Cloud
An architectural approach to managing privileged emergency access not through always-on permissions but via an auditable, short-lived control plane.
Tutorials
Service-Based Linux Hardening with AppArmor
An AppArmor guide for securing server services through process-level constraints rather than generic hardening.
Tutorials
Designing an Enterprise Management Network Overlay with Headscale
A Headscale-based management network overlay guide for providing controlled access to scattered servers and management endpoints.
Tutorials
Continuous Vulnerability Validation on Internal Assets with Nuclei
A practical Nuclei approach for scanning internal network services with low noise and tying validated findings to your operations workflow.
Tutorials
Short-Lived Certificate Automation for Internal Services with step-ca
A guide that explains a step-ca based short-lived TLS certificate generation flow for cutting long-lived certificate burden between internal services.
Tutorials
An SBOM-Based Image Admission Gate with Syft and Grype
A practical guide to admitting container images not just by a CVE list, but by component inventory and policy threshold.
Technology
A Quarantine Account for the Management Plane in Enterprise Cloud
Architectural guide covering the quarantine account approach and its boundaries when isolating management services from production resources in a cloud…
Tutorials
An Egress Traffic Policy Layer with nftables
A guide describing how to set up an nftables-based egress policy layer to control which destinations servers can reach in the outside world.
Technology
Segment-Based Resolution in Enterprise Networks with DNS Firewall
A DNS architecture that separates the resolution flow per segment, reducing abuse risk, data exfiltration, and operational blind spots.
Technology
Shared-Service VPC Decision Matrix in Enterprise Cloud
An architectural framework that explains when consolidating DNS, egress, security and observability services into a single VPC is the right call.
Technology
Certificate Lifecycle Architecture on Enterprise Platforms
An architectural approach that turns TLS certificates from a file-renewal chore into a first-class enterprise platform component.
Tutorials
Internal API Authorization Chain with Envoy ext_authz
A secure authorization pipeline you can build with the Envoy ext_authz filter to separate identity, policy, and decision logging on internal service traffic.
Tutorials
East-West Traffic Profiling with Suricata: A Practical Guide
A low-friction profiling approach with Suricata to make service-to-service traffic visible inside the data center.
Tutorials
Regional DNS Cache and Forwarder Separation with Unbound
A clean guide for separating resolution traffic across enterprise segments by configuring cache, forwarder, and access control with Unbound.
Tutorials
Just-in-Time Access to the Management Network with WireGuard
A practical WireGuard-based approach to building short-lived, auditable management access instead of permanent VPN accounts.
Technology
Secret Key Distribution Plane in ERP Infrastructures
A central secret key distribution architecture that reduces the burden of secret handling across ERP integrations and batch flows.
Technology
A Telemetry Control Plane for Enterprise Observability
An architecture that manages telemetry cost and security through a central decision layer instead of scattered agents and pipelines.
Technology
Designing the Shared Identity Boundary in the Enterprise Cloud
A shared design approach that simplifies identity, authorization, and operational boundaries in multi-account cloud setups.
Tutorials
Protecting Management APIs with mTLS on Nginx
A simple and auditable mTLS setup on Nginx for protecting management APIs with client certificates.
Technology
Integration DMZ Pattern in ERP Infrastructures
An approach for collecting partner and external service integrations in a secure intermediate layer without exposing ERP core systems directly.
Technology
Integration DMZ Design in ERP Infrastructures
An integration DMZ approach for connecting ERP systems to external services in a secure and manageable way.
Technology
Centralized Egress Design in Enterprise Networks
Principles for collecting enterprise outbound internet traffic into a visible, auditable, and scalable egress layer.
Technology
Isolated Recovery Zone in Backup Infrastructure
An approach to building an isolated recovery zone against ransomware and management mistakes, going beyond simply storing backups.
Tutorials
A Server Hardening Baseline with Ansible
A guide to making your Linux server security baseline repeatable and auditable with Ansible.
Tutorials
Runtime Security Observation with Falco
A Falco-based setup guide for surfacing suspicious runtime behavior across Linux and Kubernetes environments.
Tutorials
Privileged Access with Short-Lived Certificates
A guide to managing privileged access safely by using short-lived certificates instead of permanent SSH keys.
Tutorials
External Secrets Flow for Kubernetes Secret Rotation
A guide based on External Secrets for pulling secret data from a central vault and applying rotation in Kubernetes environments.
Technology
Zero Trust Architecture on Enterprise Networks
How to build a Zero Trust approach across enterprise networks through identity, segmentation and observability layers.
Tutorials
Cloudflare Tunnel and Reverse Proxy Guide
How to set up a secure reverse proxy structure that hides your origin IP using Cloudflare Tunnel.