hunting-bootkits-in-efi-system-partition

hunting-bootkits-in-efi-system-partition is a skill for Claude Code, Codex from adriannoes/awesome-agentic-ai. It costs 64 tokens per session (3,288 once invoked), scanned B, original, MIT.

A procedure for checking the EFI System Partition, a small disk area that firmware reads before the operating system starts. It looks for altered boot files and other signs of UEFI bootkits, which are malware that runs before normal security tools.

In plain words
What is it for?
Use it to baseline the EFI partition, verify boot loaders, hash files, scan with YARA, and detect unexpected non-EFI files during investigations.
Why use it?
Bootkits can survive operating-system reinstallation and may start before endpoint defenses. Comparing files, hashes, and scan results helps identify suspicious changes.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: positional $N argument.

Good fit Use it to baseline the EFI partition, verify boot loaders, hash files, scan with YARA, and detect unexpected non-EFI files during investigations.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/adriannoes/awesome-agentic-ai/hunting-bootkits-in-efi-system-partition
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 adriannoes/awesome-agentic-ai --skill hunting-bootkits-in-efi-system-partition
Clone the repo
git clone --depth 1 https://github.com/adriannoes/awesome-agentic-ai

Made for: Claude Code, Codex.

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 hunting-bootkits-in-efi-system-partition

README.md
[![agentmods](https://agentmods.dev/badge/skills/adriannoes/awesome-agentic-ai/hunting-bootkits-in-efi-system-partition/github.svg)](https://agentmods.dev/skills/adriannoes/awesome-agentic-ai/hunting-bootkits-in-efi-system-partition)
Your own site
<a href="https://agentmods.dev/skills/adriannoes/awesome-agentic-ai/hunting-bootkits-in-efi-system-partition"><img src="https://agentmods.dev/badge/skills/adriannoes/awesome-agentic-ai/hunting-bootkits-in-efi-system-partition/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 hunting-bootkits-in-efi-system-partition

Your own site · 80×15
<a href="https://agentmods.dev/skills/adriannoes/awesome-agentic-ai/hunting-bootkits-in-efi-system-partition"><img src="https://agentmods.dev/badge/skills/adriannoes/awesome-agentic-ai/hunting-bootkits-in-efi-system-partition.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 64 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,288 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 13 findings, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Privilege Escalation · line 51
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
  • medium Privilege Escalation · line 52
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
  • medium Privilege Escalation · line 81
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
  • medium Privilege Escalation · line 82
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
  • medium Privilege Escalation · line 158
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
  • medium Privilege Escalation · line 162
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
  • medium Privilege Escalation · line 170
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
  • medium Privilege Escalation · line 173
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
  • medium Privilege Escalation · line 180
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
  • medium Privilege Escalation · line 182
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
  • medium Privilege Escalation · line 85
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
  • medium Privilege Escalation · line 86
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
  • medium Privilege Escalation · line 123
    Commands invoke sudo or root privileges. Verify this elevated access is necessary and justified.
    Fix: Avoid sudo/root unless strictly required. Prefer least-privilege patterns. If elevation is needed, document the justification and scope.
How audits are shown
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 $0.00064 $0.03288
Opus 5 $0.00032 $0.01644
Sonnet 5 $0.00013 $0.00658
Haiku 4.5 $0.00006 $0.00329

Measured 9d ago against content hash a0f9b4e380da, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade B, and why

hunting-bootkits-in-efi-system-partition scanned grade B with 1 finding 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 9d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/agent.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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 apt-get update
cursor-claude-codex/skills/anthropic-cybersecurity-skills/skills/hunting-bootkits-in-efi-system-partition/SKILL.md · 223 lines

How it starts

The opening of the file, as written. The whole thing — 223 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Hunting Bootkits in the EFI System Partition

Overview

The EFI System Partition (ESP) is a small FAT32-formatted partition that the platform firmware reads at power-on to locate and execute the operating system's boot loader. Because it executes before the operating system, kernel, and any EDR agent, the ESP is one of the most coveted persistence locations for advanced adversaries. UEFI bootkits that live on the ESP survive OS reinstallation, disk reformatting of the OS partition, and most endpoint defenses.

This skill follows the detection research published by Eclypsium ("Enhanced Threat Detection: Bootloaders, Bootkits, and Secure Boot", and the Bootkitty and Glupteba analyses) and aligns with the ESP-hunting methodology Rapid7 documented for Velociraptor (Windows.Forensics.UEFI, Windows.Detection.Yara.UEFI). The threat context is concrete and current:

  • ESPecter (ESET, 2021) — a UEFI bootkit that persists on the ESP as a patched Windows Boot Manager (bootmgfw.efi) plus malicious kernel-mode drivers. It marked the move of UEFI threats from SPI flash to the ESP, where they are far easier to deploy.
  • BlackLotus (2023) — the first in-the-wild UEFI bootkit able to bypass Secure Boot on fully patched Windows 11 by exploiting CVE-2022-21894 ("baton drop") and staging a vulnerable signed bootmgfw.efi on the ESP.
  • Bootkitty (2024) — the first UEFI bootkit targeting Linux, dropped onto the ESP.
  • Glupteba — commodity malware whose UEFI variant replaces software on the EFI partition.

The core detection insight from Eclypsium and Rapid7 is that the bootloader normally changes only during a vendor or OS update; an out-of-band change to ESP binaries, an unsigned or untrusted-signed boot loader, or any file in the ESP root that is not under the EFI/ directory is a high-fidelity indicator of compromise. This skill builds that baseline and hunts deviations from it.

When to Use

  • During proactive threat hunts for firmware/bootkit persistence (MITRE ATT&CK T1542.003 — Pre-OS Boot: Bootkit)
  • After an incident where an adversary achieved SYSTEM/root and may have established below-OS persistence
  • When validating Secure Boot posture across a fleet and confirming boot-chain integrity
  • As a periodic integrity check, comparing the current ESP contents against a trusted golden baseline
  • When triaging hosts that show measured-boot (TPM PCR) mismatches

Read the full file on GitHub · 223 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 9d ago First seen · 223 lines · 64 tokens per session scan B a0f9b4e380da

Subscribe to this mod's changes

hunting-bootkits-in-efi-system-partition is a skill published in the GitHub repository adriannoes/awesome-agentic-ai (57 stars, last pushed 14d ago), licensed MIT. It adds 64 tokens to every session and 3,288 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it B with 1 finding (asks for root). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

Related

Other skills, from other repositories

analyzing-uefi-bootkit-persistence

Analyzes UEFI bootkit persistence mechanisms including firmware implants in SPI flash, EFI System Partition (ESP) modifications, Secure Boot bypass techniques, and UEFI variable manipulation. Covers detection of known bootkit families (BlackLotus, LoJax, MosaicRegressor, MoonBounce, CosmicStrand), ESP partition…

marysatasselshaped667/skills-collection-1 · 116 tokens

analyzing-uefi-bootkit-persistence

Analyzes UEFI bootkit persistence mechanisms including firmware implants in SPI flash, EFI System Partition (ESP) modifications, Secure Boot bypass techniques, and UEFI variable manipulation. Covers detection of known bootkit families (BlackLotus, LoJax, MosaicRegressor, MoonBounce, CosmicStrand), ESP partition…

26zl/cybersec-toolkit · 116 tokens

analyzing-uefi-bootkit-persistence

Analyzes UEFI bootkit persistence mechanisms including firmware implants in SPI flash, EFI System Partition (ESP) modifications, Secure Boot bypass techniques, and UEFI variable manipulation. Covers detection of known bootkit families (BlackLotus, LoJax, MosaicRegressor, MoonBounce, CosmicStrand), ESP partition…

pinkpixel-dev/skills-collection-1 · 116 tokens

analyzing-uefi-bootkit-persistence

Analyzes UEFI bootkit persistence (SPI flash implants, ESP modifications, Secure Boot bypass, UEFI variable manipulation) using chipsec for firmware integrity verification, detecting known families like BlackLotus, LoJax, and MoonBounce. Use for UEFI malware analysis, firmware persistence investigation, or Secure Boot…

Youngmaidainon/Agent-Level-Up · 77 tokens

todos

This chat has a shared, live TODO plan — your tasks for the conversation, which the user also edits. Read this skill and reach for the todo tools whenever a request takes more than a couple of steps. It covers the plan model (group = task, items = its steps; loose items are the user's lane), how to work it: propose…

JetBrains/thinkrail · 127 tokens

writing-workflow-skills

Use when adding a new workflow skill to pi-thinkrail-workflow, changing an existing workflow skill's role, trigger, handoff, or structure, or checking a workflow skill against the workflow system's rules. Not for authoring general-purpose skills outside this package.

JetBrains/thinkrail · 60 tokens