{"id":"hunt-ntlm-info","name":"hunt-ntlm-info","summary":"インターネットアクセス可能なIIS/SharePoint/Exchangeに関する情報開示をNTLM探し/交渉する。","body":"## Crown Jewel Targets\n\nNTLM info disclosure is a **Medium-severity finding when chained to context** — the leak itself is intentional protocol behavior (RFC-compliant NTLMSSP challenge), but on internet-exposed enterprise infrastructure it provides exact reconnaissance for the next stage of an attack. Highest-value targets:\n\n- **Internet-reachable IIS / SharePoint / Exchange / OWA** with dual-auth (Forms + NTLM, or NTLM + Kerberos)\n- **Citrix NetScaler / VMware Horizon View** internet-facing gateways with NTLM-backed AD auth\n- **Lync / Skype for Business / Teams On-Prem** edge servers\n- **WSUS / Windows Update Services** with NTLM-protected admin paths\n- **CIFS-style fileshare proxies** (HCL Sametime, IBM Notes Domino) that proxy NTLM\n- **Legacy SharePoint farms** that left NTLM enabled on the public-zone IIS binding\n\n**What makes this pay:**\n- Internal AD domain disclosure (parent-forest mapping, e.g. `customer.parent-corp.example` → tenant inside corporate-AD tree)\n- Default-Windows-hostname disclosure (`WIN-XXXXXXXXXXX` pattern signals rushed provisioning → likely default service-account passwords)\n- Timestamp leak (used in NTLMv2 hash cracking acceleration)\n- Direct attack-map enrichment for credential spraying combined with `hunt-auth-bypass` Legacy-Protocol Matrix\n\n---\n\n## Attack Surface Signals\n\n**Response headers signaling NTLM availability:**\n```\nWWW-Authenticate: NTLM\nWWW-Authenticate: Negotiate\nWWW-Authenticate: NTLM, Negotiate\nWWW-Authenticate: Negotiate, NTLM\n```\n\n**URL patterns where NTLM is commonly exposed:**\n```\n/_api/web/CurrentUser                  (SharePoint REST)\n/_vti_bin/*.asmx                       (SharePoint legacy SOAP)\n/EWS/Exchange.asmx                     (Exchange Web Services)\n/Autodiscover/Autodiscover.xml         (Exchange autodiscover)\n/owa/                                  (Outlook Web App)\n/Microsoft-Server-ActiveSync           (ActiveSync)\n/PowerShell                            (Exchange Mgmt Shell over HTTPS)\n/api/v3/                               (TeamCity, Atlassian)\n/wsus/                                 (Windows Server Update Services)\n/manager/html                          (some Tomcat behind IIS)\n/iisstart.htm                          (default IIS, sometimes reveals NTLM upstream)\n```\n\n**Tech-stack signals:**\n- IIS on the public internet (almost always NTLM-capable, even if Forms is the front)\n- SharePoint Web Front End (almost always dual-auth Forms + NTLM)\n- Exchange edge transport\n- Server header `Microsoft-HTTPAPI/2.0`, `Microsoft-IIS/*`, `IIS/*`\n\n---\n\n## Step-by-Step Hunting Methodology\n\n1. **Probe every anonymous endpoint for `WWW-Authenticate: NTLM`.** Send a vanilla GET and inspect response headers. If NTLM is offered, proceed.\n\n2. **Send a valid NTLMSSP Type-1 message anonymously.** The Type-1 base64 below requests NetBIOS-domain and Workstation info from the server:\n   ```\n   Authorization: NTLM TlRMTVNTUAABAAAAB4IIogAAAAAAAAAAAAAAAAAAAAAGAbEdAAAADw==\n   ```\n   This is the standard test Type-1 with negotiate flags `NTLMSSP_NEGOTIATE_UNICODE | NTLMSSP_NEGOTIATE_OEM | NTLMSSP_NEGOTIATE_NTLM | NTLMSSP_NEGOTIATE_ALWAYS_SIGN | NTLMSSP_NEGOTIATE_KEY_EXCH | NTLMSSP_NEGOTIATE_56 | NTLMSSP_NEGOTIATE_128 | NTLMSSP_NEGOTIATE_TARGET_INFO`. The `OS Version` field (`06 01 B1 1D 00 00 00 0F`) is Windows 7 build 7601 — accepted by virtually every NTLM responder.\n\n3. **Use a keep-alive raw socket, not Python requests / curl one-shot.** Most HTTP libraries close the connection between the Type-1 send and Type-2 reception. Use one of:\n   - Burp Repeater with `Connection: keep-alive` set explicitly\n   - Burp `mcp__burp__send_http1_request` (handles keep-alive natively)\n   - Python raw `socket` + `ssl.wrap_socket` (see Payload section)\n\n4. **Parse the Type-2 challenge from the `WWW-Authenticate: NTLM <base64>` response header.** Base64-decode the value. The structure is NTLMSSP per MS-NLMP:\n   - Bytes 0-7: literal `NTLMSSP\\0`\n   - Bytes 8-11: MessageType = `\\x02\\x00\\x00\\x00`\n   - Bytes 12-19: TargetName SecurityBuffer (len, alloc, offset)\n   - Bytes 20-23: NegotiateFlags\n   - Bytes 24-31: Server Challenge (8 bytes — useful for offline cracking)\n   - Bytes 40-47: TargetInfo SecurityBuffer (len, alloc, offset)\n   - TargetInfo body: `AV_PAIRS` array of (AvId u16, AvLen u16, Value)\n\n5. **Decode the AV_PAIRS.** The AvIds you care about:\n   - `1` = NetBIOS Computer Name\n   - `2` = NetBIOS Domain Name\n   - `3` = DNS Computer Name (FQDN of the responding server)\n   - `4` = DNS Domain Name (the AD domain)\n   - `5` = DNS Tree Name (the AD forest root)\n   - `7` = Timestamp (FILETIME, useful for NTLMv2 hash relay / cracking)\n   - `9` = Target Name (in newer NTLMSSP)\n\n6. **Map findings to severity tier:**\n   - Internet-exposed + default `WIN-XXXXXXXXXXX` hostname + corporate-AD-tree disclosure → **Medium**\n   - Internet-exposed + named-server hostname (`SPWEB01.corp.example`) + corporate-AD-tree → **Low-Medium**\n   - Intranet-only + any disclosure → **Informational**\n   - Combine with `hunt-auth-bypass` Legacy-Protocol Matrix findings on the same host → **upgrade the auth-bypass finding's severity** since the attacker has UPN/SAM format ready\n\n7. **Check the timestamp.** If `AV[7]` returns a current FILETIME within ~5s of `Date:` header, the system clock is synced — useful intel for Kerberos golden-ticket forging (out of bug-bounty scope but red-team relevant).\n\n8. **Cross-reference with subdomain enum.** The DNS Tree name often reveals the *parent forest* — e.g. `customer.parent-corp.example` reveals the customer is a sub-domain INSIDE corporate-parent AD, not a separate tenant. This is a privacy / topology-disclosure escalation that programs sometimes accept as Medium.\n\n---\n\n## Payload & Detection Patterns\n\n**Generic NTLM Type-1 anonymous probe (curl + raw socket fallback):**\n```bash\n# Most one-shot curl runs DON'T return Type-2 because the connection closes.\n# Use this as a quick probe to confirm NTLM is offered:\ncurl -sk -I -H \"Authorization: NTLM TlRMTVNTUAABAAAAB4IIogAAAAAAAAAAAAAAAAAAAAAGAbEdAAAADw==\" \\\n  \"https://target.example/_api/web/CurrentUser\" 2>&1 | grep -i \"WWW-Authenticate\"\n```\n\n**Burp `send_http1_request` (recommended for full Type-2 capture):**\n```\nGET /_api/web/CurrentUser HTTP/1.1\nHost: target.example\nAuthorization: NTLM TlRMTVNTUAABAAAAB4IIogAAAAAAAAAAAAAAAAAAAAAGAbEdAAAADw==\nConnection: keep-alive\nUser-Agent: Mozilla/5.0\n\n```\n\n**Python raw socket + AV_PAIR decoder:**\n```python\nimport socket, ssl, base64, struct, re\nfrom datetime import datetime, timezone\n\nHOST = \"target.example\"\nctx = ssl.create_default_context()\nctx.check_hostname = False\nctx.verify_mode = ssl.CERT_NONE\n\ns = ctx.wrap_socket(socket.create_connection((HOST, 443)), server_hostname=HOST)\ns.sendall(\n    f\"GET /_api/web/CurrentUser HTTP/1.1\\r\\n\"\n    f\"Host: {HOST}\\r\\n\"\n    \"Authorization: NTLM TlRMTVNTUAABAAAAB4IIogAAAAAAAAAAAAAAAAAAAAAGAbEdAAAADw==\\r\\n\"\n    \"User-Agent: Mozilla/5.0\\r\\nConnection: keep-alive\\r\\n\\r\\n\".encode()\n)\ndata = b\"\"\nwhile True:\n    chunk = s.recv(8192)\n    if not chunk: break\n    data += chunk\n    if b\"\\r\\n\\r\\n\" in data: break\n\nm = re.search(rb\"WWW-Authenticate:\\s*NTLM\\s+([A-Za-z0-9+/=]{20,})\", data, re.I)\nif m:\n    b = base64.b64decode(m.group(1).decode(\"ascii\"))\n    assert b[:8] == b\"NTLMSSP\\x00\"\n    tn_len, _, tn_off = struct.unpack_from('<HHI', b, 12)\n    ti_len, _, ti_off = struct.unpack_from('<HHI', b, 40)\n    print(f\"TargetName: {b[tn_off:tn_off+tn_len].decode('utf-16-le', errors='ignore')!r}\")\n    av_types = {1:'NetBIOS Computer Name', 2:'NetBIOS Domain Name',\n                3:'DNS Computer Name', 4:'DNS Domain Name',\n                5:'DNS Tree Name', 7:'Timestamp', 9:'Target Name'}\n    i = 0\n    ti = b[ti_off:ti_off+ti_len]\n    while i < len(ti):\n        av_id, av_len = struct.unpack_from('<HH', ti, i)\n        if av_id == 0: break\n        val = ti[i+4:i+4+av_len]\n        if av_id == 7:\n            ts = struct.unpack('<Q', val[:8])[0]\n            secs = (ts - 116444736000000000) / 10000000\n            vs = datetime.fromtimestamp(secs, tz=timezone.utc).isoformat()\n        else:\n            vs = val.decode('utf-16-le', errors='ignore')\n        print(f\"  AV[{av_id}] {av_types.get(av_id, '?'):28s}: {vs!r}\")\n        i += 4 + av_len\n```\n\n**Burp Collaborator NOT needed** for this finding class — the data leak is in the synchronous response, not via OOB.\n\n---\n\n## Common Root Causes\n\n1. **Dual-auth IIS bindings on the public zone.** Administrators leave NTLM enabled on the public-facing IIS site even when Forms auth is the intended entry point. Internal users get SSO; external attackers get the AD topology leak.\n\n2. **Default IIS Application Pool identity left as `ApplicationPoolIdentity`.** Combined with default hostname, signals provisioning never went past first-boot.\n\n3. **Server never renamed from Windows-installer-generated hostname.** Microsoft's default `WIN-XXXXXXXXXXX` 11-character pattern is the immediate tell. Sometimes also `WORKGROUP\\WIN-...` in older boxes.\n\n4. **Sub-domain joined to corporate forest without zone-isolation.** European-integrator case: a a European importer's SharePoint test environment is a child domain inside a corporate global AD, disclosed via NTLM DNS Tree Name. The customer probably intends `customer.parent-corp.example` to be operationally separate but the NTLM Type-2 reveals the forest membership to anyone who probes.\n\n5. **IIS Extended Protection NOT enabled.** When `<system.webServer><security><authentication><windowsAuthentication extendedProtection>` is `None` (the default), the NTLM challenge is sent to any anonymous client. When set to `Required`, NTLM is restricted to authenticated callers — and the AV-pair leak is mitigated.\n\n6. **No `WindowsAuthentication` removed from `applicationHost.config` for internet-exposed sites.** SharePoint Central Admin sometimes leaves this enabled even when SP zone configuration only enables Forms.\n\n---\n\n## Bypass Techniques\n\nThis skill describes a disclosure leak, not an authentication bypass. The \"bypass\" question is: *how do defenders block this AV-pair leak while still allowing legitimate NTLM auth?*\n\n| Defense | Effectiveness |\n|---|---|\n| **Disable NTLM on the public IIS binding entirely** (Forms-only) | Best — eliminates the surface |\n| **IIS Extended Protection = Required** | Restricts NTLM challenge to authenticated callers; AV-pair leak mitigated |\n| **Reverse-proxy strip `WWW-Authenticate` from anonymous responses** | Sometimes works but breaks legitimate clients |\n| **Rate-limit the Type-1 → Type-2 endpoint** | Doesn't prevent disclosure, only slows enumeration |\n| **Rename the Windows host from `WIN-XXXXXXXXXXX`** | Removes the \"lazy provisioning\" tell; doesn't stop the leak |\n| **Move the SP/Exchange farm to a child AD with no cross-trust to corporate** | Mitigates the *forest disclosure*; doesn't stop the leak |\n\nFor the attacker: there's no \"bypass\" needed — the leak is the finding.\n\n---\n\n## Gate 0 Validation\n\nBefore writing the report, confirm:\n\n1. **What can the attacker do RIGHT NOW with this disclosure?**\n   - Internet-exposed + default hostname + corporate forest disclosed → **Medium**: attacker has UPN format for `hunt-auth-bypass` matrix probes, plus knows server has likely-default service accounts.\n   - Intranet-only or only NetBIOS name → **Informational**.\n\n2. **Does the program accept information-disclosure findings without a chained impact?**\n   - Many programs (Microsoft, large enterprise VDPs) DO accept this when the leaked info includes internal AD topology.\n   - Many programs (Shopify, GitHub) reject info disclosure without a chained impact.\n   - Read the program scope before submitting; if borderline, chain with a Tier-A finding from `hunt-auth-bypass`.\n\n3. **Can you reproduce in <5 minutes from a fresh shell?**\n   - The Python snippet above is the canonical reproduction. Include it verbatim in the report.\n\n---\n\n## Real Impact Examples\n\n### Scenario A — Enterprise SharePoint inside parent corporate AD\n\nTarget: `https://target-portal.example/` — a enterprise dealer portal (test mirror) operated by a system integrator.\n\nSending the anonymous Type-1 message to `/_api/web/CurrentUser` returned a Type-2 challenge whose AV_PAIRS decoded to:\n\n```\nNetBIOS Domain Name:    <CustomerName>\nNetBIOS Computer Name:  WIN-XXXXXXXXXXX\nDNS Domain Name:        customer.parent-corp.example\nDNS Computer Name:      WIN-XXXXXXXXXXX.customer.parent-corp.example\nDNS Tree Name:          customer.parent-corp.example\nTimestamp:              2026-05-13T15:55:37.922Z\n```\n\nThree escalation paths:\n1. **Default Windows-installer hostname (`WIN-XXXXXXXXXXX`)** — server was never renamed after OS install; strong signal of lazy provisioning. Likely default service-account passwords on the SQL backend, default WSUS config, etc.\n2. **Sub-domain inside corporate-parent AD (`customer.parent-corp.example`)** — the customer is a child domain inside <ParentCorp>'s global Active Directory. A compromise of this test farm has potential cross-trust to corporate-parent.\n3. **UPN format known** — combined with `hunt-auth-bypass`'s discovery of an anonymous brute-force endpoint on `/_vti_bin/Authentication.asmx`, the attacker has both the credential format (`firstname.lastname@customer.parent-corp.example` or `<CustomerName>\\firstname.lastname`) and the unlimited submission endpoint.\n\nReported severity: **Medium**, with a note that the chain with the Authentication.asmx anonymous brute-force makes the combined attack Critical.\n\n### Scenario B — Exchange edge with NTLM-protected EWS\n\nTarget: `https://mail.example.com/EWS/Exchange.asmx`. Type-1 probe returns Type-2 with DNS Tree Name `corp.example.com` and DNS Computer Name `MAIL01.corp.example.com`. Confirms the Exchange edge is domain-joined to corporate AD (rather than running in a DMZ-isolated AD). For an attacker with the matching `hunt-mfa-bypass` / `hunt-auth-bypass` chain, the leaked UPN format and server-name format accelerate credential spraying by removing the recon step. Reported severity: Low-Medium depending on program.\n\n### Scenario C — Intranet-only intentional leak (not a finding)\n\nTarget: `https://intranet.corp.example` (clearly internal, behind VPN). Type-1 returns full AV-pair set. Not reportable — this is intended NTLM behavior on intranet, and the disclosure is to authenticated VPN users who already see the same data via `nltest /dsgetdc:corp.example.com`. Recognize and drop.\n\n---\n\n## Related Skills & Chains\n\n- **`hunt-sharepoint`** — SharePoint farms emit anonymous Type-2 challenges on `/_vti_bin/` by default; this is one of the most reliable ways to get internal AD topology. Chain primitive: SharePoint discovered → NTLM Type-2 capture on `/_vti_bin/Lists.asmx` → `hunt-ntlm-info` AV_PAIR decode → internal forest name → `m365-entra-attack` ROPC spray on Entra tenant tied to that forest.\n- **`m365-entra-attack`** — Leaked NetBIOS domain + UPN suffix is the missing piece for a credible password spray. Chain primitive: NTLM Type-2 yields `corp.example.com` DNS tree → cross-reference Entra tenant via `https://login.microsoftonline.com/corp.example.com/.well-known/openid-configuration` → `m365-entra-attack` AADSTS error-differential username enumeration on resolved tenant.\n- **`hunt-aspnet`** — IIS sites running ASP.NET frequently expose NTLM on management paths. Chain primitive: NTLM Type-2 on `/owa/`, `/ecp/`, `/rpc/`, `/aspnet_client/` → confirm IIS + ASP.NET version → `hunt-aspnet` ViewState / `.axd` enumeration on same host.\n- **`offensive-osint`** — The hostname pattern `WIN-XXXXXXXXXXX` signals lazy provisioning and predicts other weak hygiene. Chain primitive: NTLM Type-2 returns default-installer hostname → flag as low-maturity environment → `offensive-osint` deep recon (cert transparency, GitHub leakage, breach corpus correlation) is high-yield on this org.\n- **`triage-validation`** — Most NTLM info-disclosure findings die at the 7-Question Gate on \"is this exploitable\" — pure topology disclosure is Low/Informational. Chain primitive: pull every NTLM-info finding through `triage-validation` BEFORE writing it up; only report if (a) leaks UPN format that accelerates spray, or (b) leaks production hostname mapping (`redteam-report-template` for the chain-narrative).","author":"@elementalsouls","ownerProfile":null,"authorContacts":null,"sourceUrl":"https://github.com/elementalsouls/Claude-BugHunter/tree/main/skills/hunt-ntlm-info","license":"MIT","category":null,"lang":"en","tokens":4080,"stars":0,"calls30d":1,"claimed":false,"visibility":"public","origin":"crawler","version":"0.1.0","createdAt":"2026-08-22","updatedAt":"2026-08-22","files":[],"requires":{"mcp":["burp"],"tools":[]},"safety":{"flags":[],"scannedAt":"2026-08-22","hasScripts":false,"networkEndpoints":["intranet.corp.example","login.microsoftonline.com","mail.example.com","target-portal.example","target.example"]}}