hunt-aspnet

⚠️ AUTHORIZED USE ONLY This skill is for educational purposes or authorized security assessments only. You must have explicit, written permission from the system owner before using this tool. Misuse of this tool is illegal and strictly prohibited.

Mandatory confirmation gate Before running any command that probes, exploits, changes, persists on, extracts data from, or attempts credential access against a target:

1. Ask the user to state the exact target URL, IP, account, or resource.
2. Ask the user to confirm written authorization and the permitted scope.
3. Show the exact command(s) and explain their expected effect.
4. Wait for explicit confirmation in the current conversation.

Without that confirmation, remain read-only and provide defensive guidance only. Prefer a sandbox, disposable VM, or controlled lab.

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 AJAX — Telerik.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

URL patterns to probe:

/trace.axd                            (per-app trace viewer; sometimes anon-accessible)
/elmah.axd                            (ELMAH error log viewer)
/elmah.axd/?id=...                    (ELMAH RCE / stack-trace leak)
/*.svc                                (WCF services)
/*.svc?wsdl                           (WCF WSDL)
/*.svc/mex                            (Metadata Exchange)
/*.asmx                               (legacy SOAP)
/*.asmx?WSDL                          (legacy SOAP description)
/*.asmx?disco                         (legacy discovery)
/Telerik.Web.UI.WebResource.axd       (Telerik AJAX components)
/ChartImg.axd                         (DataVisualization controls; historic deserialization)
/ScriptResource.axd                   (script resource handler; sometimes leaks paths)
/WebResource.axd                      (web resource handler)
/_vti_bin/*                           (SharePoint Web Service Forwarder)
/api/                                 (Web API 2.x is ASP.NET on classic framework)
/signin                               (often FedAuth / WS-Federation)

Tech-stack signals:

• Server: Microsoft-IIS/10.0 (or /8.5, /7.5) — confirmed Windows + IIS

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