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analyzing-firmware-images

analyzing-firmware-images is a skill for Claude Code from trilwu/secskills. It costs 91 tokens per session (3,819 once invoked), scanned D, original, MIT.

A guide for examining firmware images, the software files built into devices such as routers and IoT hardware. It covers extracting their files and reviewing their programs, interfaces, services, and security settings.

In plain words
What is it for?
Use it to inspect .bin, .img, .chk, or .trx updates, look for hardcoded credentials and keys, review web interfaces, assess device attack surfaces, analyze different processor types, emulate images, and check cryptography.
Why use it?
It gives structure to the difficult task of assessing software that may not have been updated since the device shipped. It helps uncover embedded secrets, unsafe update checks, exposed services, and other security risks.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the secskills-core plugin — 30 skills shipped together

not rated 185repo +3 2mo ago D scan 91 tokens original MIT

Good fit Use it to inspect .bin, .img, .chk, or .trx updates, look for hardcoded credentials and keys, review web interfaces, assess device attack surfaces, analyze different processor types, emulate images, and check cryptography.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/trilwu/secskills/analyzing-firmware-images
View source ↗ trilwu/secskills trilwu.github.io
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add trilwu/secskills --skill analyzing-firmware-images
Clone the repo
git clone --depth 1 https://github.com/trilwu/secskills

Made for: Claude Code.

Or install secskills-core, the plugin that ships this one along with the rest of its 30 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for analyzing-firmware-images

README.md
[![agentmods](https://agentmods.dev/badge/skills/trilwu/secskills/analyzing-firmware-images/github.svg)](https://agentmods.dev/skills/trilwu/secskills/analyzing-firmware-images)
Your own site
<a href="https://agentmods.dev/skills/trilwu/secskills/analyzing-firmware-images"><img src="https://agentmods.dev/badge/skills/trilwu/secskills/analyzing-firmware-images/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for analyzing-firmware-images

Your own site · 80×15
<a href="https://agentmods.dev/skills/trilwu/secskills/analyzing-firmware-images"><img src="https://agentmods.dev/badge/skills/trilwu/secskills/analyzing-firmware-images.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 91 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,819 The whole file, excluding the scripts and references it only reads on demand.
Security scan D 2 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00091 $0.03819
Opus 5.5 $0.00036 $0.01528
Sonnet 5.5 $0.00018 $0.00764
Haiku 4.5 $0.00009 $0.00382

Measured 2mo ago against content hash 10d45ac46d14, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade D, and why

analyzing-firmware-images scanned grade D with 2 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Asks for rootmediumPrivilege escalation

A mod that escalates privileges can change anything on the machine, not only the project.

sudo chroot rootfs/ /usr/sbin/httpd

Reaches for credential fileshighPrivilege escalation

SSH keys, cloud credentials, git-credentials, .npmrc, /etc/shadow: reading these is how a config file becomes a credential leak.

cat rootfs/etc/shadow
secskills-core/skills/analyzing-firmware-images/SKILL.md · 381 lines

How it starts

The opening of the file, as written. The whole thing — 381 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Analyzing Firmware Images

Firmware is a frozen Linux (or RTOS) image, and its security froze with it. Hardcoded credentials, command injection in CGI scripts, unsigned update packages, and debug interfaces left enabled are not edge cases -- they are the baseline. The work is extraction, orientation, and then asking the same questions you would ask of any system, with the knowledge that nobody has patched this one since it shipped.

When to Use

  • Extracting and analyzing a firmware update file (.bin, .img, .chk, .trx)
  • Reviewing IoT device security posture from a firmware image
  • Looking for hardcoded credentials, keys, or secrets in device firmware
  • Assessing the attack surface of an embedded device or router
  • Evaluating update mechanisms and signature verification
  • Analyzing a bare-metal or RTOS image from a microcontroller

When NOT to Use

  • Standard x86/x64 binary reverse engineering -- use analyzing-binaries
  • Malware sample analysis -- use analyzing-malware
  • Source code is available -- use auditing-code-for-vulnerabilities

Firmware Acquisition

Before analysis comes acquisition. The method determines what you get.

Method What you get Notes
Vendor download Update package, often compressed or encrypted Check support portals, FTP servers, and FCC filings
OTA sniffing Update payload in transit mitmproxy or tcpdump on the device's update channel; many devices use plain HTTP
UART/serial console Shell access, bootloader interaction Three wires (TX, RX, GND); identify with a multimeter or logic analyzer
JTAG/SWD Full memory read, debug access Requires pin identification; JTAGulator, OpenOCD
Chip-off Raw flash contents (NAND/NOR) Desolder the flash chip; read with a programmer (CH341A, FlashcatUSB); last resort
Bootloader extraction Dump via U-Boot md or sf read commands If the bootloader shell is accessible over UART

For OTA interception, configure the device to proxy through mitmproxy. Many devices ignore proxy settings -- ARP spoofing or a transparent bridge may be required. If the update is over HTTPS, check whether the device validates certificates at all; a surprising number do not.

Read the full file on GitHub · 381 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2mo ago First seen · 381 lines · 91 tokens per session scan D 10d45ac46d14

Subscribe to this mod's changes

analyzing-firmware-images is a skill published in the GitHub repository trilwu/secskills (185 stars, last pushed 2mo ago), licensed MIT. It adds 91 tokens to every session and 3,819 once invoked, about $0.0004 per session on Opus 5.5. A static security scan graded it D with 2 findings (asks for root, reaches for credential files). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Code reviewHardware and IoTSecurityskills
Related

analyzing-firmware-images compared with skills from other repositories

analyzing-firmware-images next to 6 skills from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
analyzing-firmware-imagestrilwu/secskillsSkill1852mo agoMITD91Claude Code
code-review-facilitatorwedsamuel1230/arduino-skillsSkill242mo agoMITA68Claude Code
cardputer-buddyanthropics/claude-plugins-officialSkill46kyesterdayApache-2.0A109Claude Code
gke-compute-classesgoogle/skillsSkill22kyesterdayApache-2.0A83Claude Code, Codex
developer-device-platform-basicsgoogle/skillsSkill22kyesterdayApache-2.0A57Claude Code, Codex
offensive-wifiSnailSploit/Claude-RedSkill10k25d agoMITA183Claude Code, Codex
agent-watchdogBuilderIO/skillsSkill4.6k4d agoMITA115Claude Code, Codex