Stop BEC Invoice Fraud — Detect Vendor-Impersonation Tampering
HTPBE? is a REST API that catches the BEC vendor-impersonation pattern: a real invoice from a real vendor, intercepted in transit, with one field changed — the IBAN, the SWIFT/BIC, the wire-routing line, the beneficiary name. Every other check downstream still passes; the structural fingerprint of the editing session does not. In a business email compromise attack, the vendor name, amount, and invoice number are all legitimate. Only the payment destination changed. That single edit leaves a forensic trace HTPBE? finds before the wire goes out.
The problem
Modern document fraud is invisible to visual review
A growing class of document fraud opens a genuine PDF, edits a balance, a date, or a beneficiary, and re-saves it. Visually nothing changes — the document passes pixel-level review, layout review, and KYC.
Structural PDF analysis reads the layers rendering engines never expose: revision history, object structure, signature coverage maps. That is where edits leave fingerprints they cannot wipe.
Common tampering patterns
- Modified balances or totals after export
- Swapped IBAN or beneficiary on invoices
- Post-signature edits on contracts
- Backdated issue and modification dates
- Fabricated documents from consumer PDF tools
What this looks like
How BEC fraud lands a tampered invoice on your AP queue
Three real fraud mechanics we catch at the structural PDF layer.
IBAN-swap fingerprint — producer changed after vendor export
The genuine vendor invoice was rendered by SAP, NetSuite, Xero, QuickBooks, or another accounting platform — producer field carries that engine’s signature. The BEC operator opens it in a desktop PDF editor (Acrobat, Foxit, an online editor) just long enough to overtype the IBAN and re-export. The producer field no longer matches an accounting engine — the smoking gun for an in-flight edit.
Last-minute beneficiary-name swap on a real-vendor invoice
Some BEC variants change only the beneficiary-name line under the IBAN to a similar-looking entity (“Acme Holdings Ltd” instead of “Acme Ltd”). Visual review treats it as the same vendor; the editing session leaves an incremental update record in the xref chain anyway. That extra revision layer is what HTPBE? returns.
ModDate postdates the printed invoice date
The invoice date printed on the page and the PDF’s internal ModDate are independent fields. An attacker overtyping the IBAN cannot rewrite the ModDate without specialised tooling. A ModDate later than the printed invoice date on a vendor PDF is a direct in-transit-tampering signal.
Vendor digital signature stripped or invalidated
Enterprise accounting platforms often sign invoices on export. The BEC editor cannot keep the signature valid after editing; in many cases the attacker simply strips it. An invoice from a vendor whose other invoices in your system are signed, but this one is not — that is the BEC fingerprint.
The detection gap
KYC platforms check the document. HTPBE? checks the file.
Two different checks — both matter.
KYC & identity platforms
Plaid · Persona · Alloy · Jumio
- Is this a real bank statement template?
- Does the account number match the identity?
- Is the document format consistent with the issuing bank?
Detects fake documents. Does not detect edited real documents.
HTPBE? tamper detection API
Structural PDF integrity
- Was this specific PDF file modified after it was generated?
- Do metadata timestamps match the file structure?
- Were digital signatures valid at the time of signing?
What HTPBE? checks
Detection capabilities
Deterministic structural signals. No probabilistic scores, no model training.
Producer signature mismatch
The PDF claims to come from one tool but the binary structure points to another. The first signal of post-export editing.
Incremental update trail
Every save after the original creates an incremental update. Long chains mean multiple editing sessions on the same file.
Multiple xref tables
Each editing session adds a new cross-reference table. Genuine institutional PDFs have one. Tampered PDFs have several.
Modification timestamp gap
A real PDF has matching CreationDate and ModDate. Months between them is a high-confidence forgery signal.
Digital signature validation
When a digital signature exists, we verify the coverage map. Modifications after signing return certain-confidence verdicts.
Font and object consistency
Edited text introduces new font subsets or objects with origin patterns inconsistent with the rest of the document.
Integrate in minutes
Two HTTP calls, deterministic verdict
Buyers can skip this section — developers, the integration is two HTTP calls.
Request — POST /v1/analyze
curl -X POST https://api.htpbe.tech/v1/analyze \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{"url": "https://your-storage.com/document.pdf"}'Response — JSON verdict
{
"id": "3f9c8b7a-2e1d-4c5f-9b8e-7a6d5c4b3a21",
"status": "modified",
"modification_confidence": "high",
"modification_markers": [
"Multiple xref tables detected",
"Different creation and modification dates"
],
"creator": "Microsoft Word",
"producer": "Adobe PDF Library 15.0",
"has_incremental_updates": true,
"xref_count": 3
}POST a public PDF URL, get back a check ID, then GET the verdict. The API is the same regardless of document type — the structural markers in the response describe the specific tampering signals detected.
Pricing
Self-serve plans, no sales call
All plans include the same forensic checks. Pick the quota that matches your monthly document volume.
manualStarter
$15/mo
30 checks/mo
Manual spot-checks and integration testing
most commonGrowth
$149/mo
350 checks/mo
Active document processing pipelines
high volumePro
$499/mo
1,500 checks/mo
High-volume automation and API integrations
Enterprise (unlimited, on-premise available) — see full pricing
API key on signup. Free test environment on every plan. No card required.
Customer Stories
Teams that stopped document fraud
Compliance, finance, and risk teams use HTPBE? to catch manipulated PDFs before they become costly mistakes.
Caught an invoice where the total had been changed by less than a thousand dollars. Without this I would have approved it without a second look.
Sarah M.
AP Manager
United States
We had three applicants in the same week with bank statements that looked completely fine. Two of them were flagged as modified. You simply cannot see this by reading the document — it is in the file structure.
Lars V.
Risk Analyst, Online Lending
Netherlands
Salary slips were coming with altered figures. We identified two problematic files before the placement was finalised.
Priya K.
HR Operations Lead
India
Since we started checking documents this way, we stopped two applications early in the process that would have been very difficult to reverse later.
Julien R.
Fraud Analyst, Fintech
France
Some applicants were sending PDFs that looked authentic but had been edited in ways not visible to the eye. We now ask for checked originals when something is flagged. Already saved us from a few bad decisions.
Marta S.
Compliance Coordinator
Spain
One invoice was caught because there was a mismatch between the document dates and structure. That particular case would have cost us significantly.
Tariq A.
Finance Manager
United Arab Emirates
FAQ
Frequently asked questions
How do BEC invoice attacks actually work?
Can it detect if just the bank account number was changed?
How do I add this to our invoice approval workflow?
What if the invoice was created in Word?
Secure your workflow
Create your account — API key on signup, free test environment on every plan.
From $15/mo. No sales call. Cancel any time.