T00th1ess

Reverse EngineeringJun 30, 202614 min read

Firmware and eMMC

Explains firmware and eMMC from an embedded-device perspective, covering their roles, boot flow, partition layout, extraction, and analysis.

SystemsJun 16, 202612 min read

BPF LRU Per-CPU Hash Maps

Explains the structure, lookup and update behavior, eviction policy, concurrency model, and use cases of BPF LRU per-CPU hash maps.

SystemsJun 15, 20262 min read

APIs and ABIs

Distinguishes source-level APIs from binary-level ABIs, focusing on compatibility and function-call boundaries.

SystemsJun 14, 202611 min read

Process Control Blocks

Explains the fields in a process control block, process state transitions, and its role during context switches.

SystemsJun 12, 202613 min read

The TLB-Hit Model

Generalizes the TLB fast-path idea into a cache model for repeated policy decisions and analyzes its performance trade-offs.

SystemsJun 11, 202615 min read

eBPF for Windows

Explains the eBPF for Windows execution architecture, verifier, program and attach types, and networking and security use cases.

SystemsJun 09, 202615 min read

eBPF

Explains the eBPF load, verification, and execution pipeline, with a focus on maps, helpers, and attach points.

SystemsJun 09, 202613 min read

BPF

Explains why classic BPF filters packets in the kernel and how its filter instructions, virtual machine, and tcpdump workflow fit together.

SystemsJun 06, 20262 min read

Mutual Exclusion

Explains how mutual exclusion prevents race conditions around shared resources and summarizes the requirements of correct synchronization.

SystemsJun 06, 20264 min read

Critical Sections

Explains how race conditions arise in critical sections and how locks, mutexes, semaphores, and spinlocks protect them.

SystemsJun 05, 20261 min read

Busy Waiting

Explains how busy waiting consumes CPU while waiting for a lock, along with its benefits, costs, and appropriate use cases.

SystemsJun 05, 20261 min read

Context Switching

Explains how processes and threads save and restore execution state during context switches and where the overhead comes from.

SystemsJun 05, 20263 min read

Spinlocks and Mutexes

Compares spinlocks and mutexes by waiting behavior, context-switch cost, and the conditions under which each is appropriate.

Reverse EngineeringMay 18, 202611 min read

Calling Conventions

Compares major x86 and x86-64 calling conventions by argument passing, return values, and stack cleanup rules.

CTFMay 17, 20265 min read

Stack Canaries

Explains how stack canaries detect stack buffer overflows, including placement, verification, compiler options, and bypass conditions.

CTFMay 17, 20261 min read

Shellcode: ORW Shellcode

Builds Linux x86-64 ORW shellcode that opens a file, reads it, and writes its contents using syscalls.

1-Day AnalysisMay 13, 20264 min read

1-Day: CVE-2026-28466

Analyzes an authorization-bypass RCE in OpenClaw caused by failing to sanitize approval fields forwarded through node.invoke.

1-Day AnalysisMay 12, 20264 min read

1-Day: CVE-2026-26954

Analyzes a SandboxJS escape that bypasses shallow taint tracking and exposes the host Function constructor.

1-Day AnalysisMay 11, 20264 min read

1-Day: CVE-2026-3672

Analyzes a blind SQL injection in JeecgBoot caused by dynamic filterSql concatenation and incomplete WAF validation.

1-Day AnalysisMay 10, 20262 min read

1-Day: CVE-2026-21236

Summarizes a Windows AFD.sys heap buffer overflow that allows a local attacker to escalate privileges to SYSTEM.

1-Day AnalysisMay 09, 20262 min read

1-Day: CVE-2026-33017

Analyzes a Langflow RCE caused by missing authentication on a public build API and passing attacker-controlled data to exec.

SystemsApr 12, 202610 min read

The eBPF VM

Explains the in-kernel eBPF execution model through its registers, bytecode, verifier, JIT compiler, helpers, and maps.

Reverse EngineeringJan 23, 20261 min read

Installing IDA Free

Shows how to download IDA Free on Windows 11, obtain a license key, apply it, and launch the application.

SecurityJan 23, 20262 min read

Block Ciphers: AES

Explains the SPN structure used by AES, the roles of confusion and diffusion, and how it differs from the Feistel structure in DES.

SecurityJan 23, 20261 min read

Cryptography: Attacks on Classical Ciphers

Explains brute-force key search and frequency analysis, including why monoalphabetic substitution ciphers are vulnerable.

CTFJan 22, 20261 min read

Using Netcat (nc)

Covers installing Netcat or Ncat on Ubuntu and Windows and using it to connect to a remote host and port.

GeneralJan 22, 20261 min read

Computer Science Basics, Part 1

Briefly defines computer science and compares big-endian and little-endian byte ordering.

DevelopmentOct 19, 20251 min read

What Is a Database?

Explains why persistent storage is needed, compares file systems with databases, and clarifies where SQLite fits.

DevelopmentOct 09, 20251 min read

Microfrontend Architecture

Explains how microfrontends divide a large frontend into independently deployable applications and summarizes the trade-offs.

DevelopmentOct 09, 20251 min read

Spring Framework

Explains why Spring was created and how dependency injection and POJOs improve productivity, maintainability, and testing.

GeneralOct 08, 20253 min read

2025 Dong-A AI Forum

Records key points from the 2025 Dong-A AI Forum on generative, agentic, and physical AI and their industrial applications.

DevelopmentAug 03, 20251 min read

TypeScript vs. JavaScript

Compares JavaScript's dynamic typing with TypeScript's static checks and shows what remains after compilation.

DevelopmentAug 03, 20251 min read

Express.js

Explains routing, middleware, and request-response handling in the Express web framework for Node.js.

DevelopmentJul 22, 20251 min read

HTTP

Summarizes HTTP's connectionless and stateless behavior, the role of cookies and sessions, and the security difference provided by HTTPS.

DevelopmentJul 20, 20252 min read

C: Pointers

Introduces C pointers through declaration, initialization, address-of operations, dereferencing, and function arguments.

DevelopmentJul 20, 20251 min read

C: Arrays

Introduces one- and two-dimensional arrays in C, including declaration, initialization, indexing, and row-major memory layout.

GeneralJun 29, 20252 min read

Cyber Guardians: Basic Linux Commands

Records basic Linux command practice in Ubuntu, including ls, cd, pwd, file, clear, less, and mkdir.

SecurityJun 29, 20251 min read

Hyundai AutoEver White Hat: Introduction to Information Security (2)

Summarizes attacker motivations and ROI, asset identification, and the security practitioner's approach to emerging threats.

YuSung Han / T00th1ess

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