hunt-aspnet

hunt-aspnet is a skill for Claude Code from elementalsouls/Claude-BugHunter. It costs 98 tokens per session (4,884 once invoked), scanned A, original, MIT.

A set of instructions for checking ASP.NET applications, Microsoft's web application technology, for platform-specific security weaknesses. It focuses on issues such as unsafe ViewState handling, exposed diagnostic pages, leaked keys, and insecure settings.

In plain words
What is it for?
Use it to examine Web Forms sites, WCF services, SharePoint, Sitecore, Telerik components, and other ASP.NET-based applications for information disclosure, authentication weaknesses, and possible code execution paths.
Why use it?
It narrows a broad security review to weaknesses that are easy to miss in older or specialized ASP.NET systems.

Skill for Claude Code

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

Part of the Claude-BugHunter plugin — 11 skills, 15 commands shipped together

Good fit Use it to examine Web Forms sites, WCF services, SharePoint, Sitecore, Telerik components, and other ASP.NET-based applications for information disclosure, authentication weaknesses, and possible code execution paths.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/elementalsouls/claude-bughunter/hunt-aspnet
About the project

Claude Code Spec Workflow is a set of Claude Code commands and agents that organizes software work into documented stages for new features and bug fixes. It is for developers who want Claude Code to handle requirements, design, implementation, issue resolution, and verification through repeatable workflows, with the catalogue entries providing the associated commands and agents.

elementalsouls/Claude-BugHunter · 4,298 stars · on GitHub · elementalsouls.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 elementalsouls/Claude-BugHunter --skill hunt-aspnet
Clone the repo
git clone --depth 1 https://github.com/elementalsouls/Claude-BugHunter

Made for: Claude Code.

Or install Claude-BugHunter, the plugin that ships this one along with the rest of its 11 skills, 15 commands.

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 hunt-aspnet

README.md
[![agentmods](https://agentmods.dev/badge/skills/elementalsouls/claude-bughunter/hunt-aspnet/github.svg)](https://agentmods.dev/skills/elementalsouls/claude-bughunter/hunt-aspnet)
Your own site
<a href="https://agentmods.dev/skills/elementalsouls/claude-bughunter/hunt-aspnet"><img src="https://agentmods.dev/badge/skills/elementalsouls/claude-bughunter/hunt-aspnet/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 hunt-aspnet

Your own site · 80×15
<a href="https://agentmods.dev/skills/elementalsouls/claude-bughunter/hunt-aspnet"><img src="https://agentmods.dev/badge/skills/elementalsouls/claude-bughunter/hunt-aspnet.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 98 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,884 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 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: 2 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 Data Exfiltration · line 125
    Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
    Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
  • medium Tool Misuse · line 137
    Tool defaults are unsafe or overly permissive (e.g. disabled TLS verification, no authentication, world-writable permissions). Unsafe defaults widen the attack surface.
    Fix: Override unsafe defaults with secure settings (verify=True, auth required, restrictive permissions). Review and harden all tool configurations.
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 $0.00098 $0.04884
Opus 5 $0.00049 $0.02442
Sonnet 5 $0.00020 $0.00977
Haiku 4.5 $0.00010 $0.00488

Measured 12d ago against content hash 1606594f88ee, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

hunt-aspnet scanned grade A 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 12d 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -sk -X POST "https://target.example/page.aspx" \
Origin

Copies of this mod

2 near-identical copies found in the catalogue:

skills/hunt-aspnet/SKILL.md · 278 lines

How it starts

The opening of the file, as written. The whole thing — 278 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Crown Jewel Targets

ASP.NET deserialization bugs pay among the highest amounts in bug bounty when they reach RCE. Even when patched, the disclosure-tier findings (signed-only ViewState, dual-parser differential, request-validator quirks) reliably pay Low-Medium.

Highest-value targets:

  • SharePoint farms (any version — 2013/2016/2019/SE) — sign-only ViewState + permissive ToolPane.aspx + anonymous FormDigest creates the CVE-2025-53770 ToolShell precondition chain
  • Telerik UI for ASP.NET AJAXTelerik.Web.UI.WebResource.axd is a documented RCE sink when keys leak (CVE-2017-11317, CVE-2017-11357, CVE-2019-18935)
  • Classic ASP.NET Webforms enterprise apps — banking portals, dealer portals, HR systems left on .NET Framework 4.x
  • WCF services (*.svc?WSDL) — often forgotten admin endpoints with looser auth than the main app
  • Sitecore CMS — ViewState + Sitecore-specific deserialization chains (CVE-2021-42237)
  • DotNetNuke (DNN) — historic ViewState RCE chains
  • Umbraco CMS — ViewState + custom deserialization sinks

Asset types that pay most: internet-reachable ASP.NET Webforms apps > WCF admin services > Telerik-integrated sites > Classic ASP.NET MVC with VSF (very rare)


Attack Surface Signals

Response headers indicating ASP.NET:

X-AspNet-Version: 4.0.30319          (classic — disclosure on its own)
X-Powered-By: ASP.NET
X-AspNetMvc-Version: 5.2
Server: Microsoft-IIS/10.0
Set-Cookie: ASP.NET_SessionId=...
Set-Cookie: .ASPXAUTH=...            (Forms auth cookie)
Set-Cookie: .ASPXFORMSAUTH=...
Set-Cookie: ASP.NET_SessionId=...; SameSite=None  (suggests cross-origin embedding)

Body signals (in form HTML):

<input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="..." />
<input type="hidden" name="__VIEWSTATEGENERATOR" id="__VIEWSTATEGENERATOR" value="..." />
<input type="hidden" name="__VIEWSTATEENCRYPTED" id="__VIEWSTATEENCRYPTED" value="" />
                                        ↑ EMPTY = signed-only, not encrypted = exploitable if key leaks
<input type="hidden" name="__EVENTVALIDATION" id="__EVENTVALIDATION" value="..." />
<input type="hidden" name="__REQUESTDIGEST" id="__REQUESTDIGEST" value="0x...,...">
                                        ↑ SharePoint CSRF token; if anon-issued, see hunt-sharepoint

Read the full file on GitHub · 278 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. 12d ago First seen · 278 lines · 98 tokens per session scan A 1606594f88ee

Subscribe to this mod's changes

hunt-aspnet is a skill published in the GitHub repository elementalsouls/Claude-BugHunter (4,298 stars, last pushed 6d ago), licensed MIT. It adds 98 tokens to every session and 4,884 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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