qr code in image-only email not extracted by gateway ocr and phish reached inboxes

TL;DR

Make the image itself scannable or make the lure harmless: check whether your gateway offers QR extraction or image OCR in its advanced settings and enable it in audit mode, add a banner for external image heavy mail, and teach users that a QR code in unsolicited mail is a link they cannot preview, to be reported rather than scanned. A picture of text defeats text filters completely, which is exactly why this format is now a standard campaign shape.

qr code in image-only email not extracted by gateway ocr and phish reached inboxes

Use this when

• Users received mail that is essentially one image containing text and a QR code.
• The gateway log shows no URL extracted and no verdict on the QR target.
• Phones, not workstations, are where users end up opening the target page.

Not for this skill when

• The QR code is in a PDF or Office attachment. Attachment detonation settings are the first place to look.
• The image mail is a legitimate newsletter format your users subscribe to. Use sender specific handling, not a global image rule.

Steps

1. Save a sample and extract the QR target yourself with an offline decoder in a safe environment, and record the destination domain. Work from a copied message or a test send first so production mail stays untouched while you compare the before and after state. Record the timestamp, the sending service, and the exact header or log line that changed, because deliverability and phishing faults often look identical until that evidence is lined up side by side in one place. Verify: the QR target is decoded and recorded without visiting it on a work device
2. Review gateway capabilities for QR code extraction, image OCR, and image only message scoring, including any licence tier requirement. Do not change more than one setting at a time here. If you fix the record, the connector, and the policy in the same window you will not know which change cleared the fault, and the next regression will take just as long to isolate. Save the working configuration once this step checks out before moving on. Verify: the available controls in your product are listed with their licence state
3. Enable QR or OCR scanning in audit or warn mode and test with the saved sample resent to a test mailbox. Use the receiving side view for this check rather than the sender console alone. Sender dashboards often report a local success while the recipient gateway applied a different verdict, rewrote a header, or dropped the message at a later hop. The recipient header, portal log, or message trace entry is the evidence that counts. Verify: the test copy produces an extracted URL or an image only warning in the log
4. Add or tune the external sender banner for image heavy mail from first time senders. Keep any exception you create narrow and time boxed. Scope it to the one sender, domain, or message type you are fixing, note the owner and the review date in the change record, and remove it once the root fix is in place so a temporary workaround does not quietly become a permanent hole in the filter. Verify: a test external image mail arrives with the banner visible
5. Publish a short user note showing the campaign style and the rule: report QR mail, do not scan it with a personal phone. Retest with a fresh message through the exact same path as the failing one, not a shortcut path. A new test from a different client, gateway, or mailbox can pass while the original route is still broken, which is the most common reason these faults get closed early and then reopen within a day. Verify: the note is published and the reporting route is stated in it

Why it happens

Quishing works because the mail system sees a harmless image while the user phone sees a link. The scan happens on an unmanaged device, outside the browser protections and conditional access the organisation relies on, and the page harvests credentials with the user feeling they were careful because they never clicked anything in email. Gateways have begun extracting QR targets, but coverage varies wildly by product and licence, leaving a gap awareness has to cover.

Variants and edge cases

qr code image only email not extracted gateway ocr phish inboxes

The extraction failure wording from gateway logs.

quishing qr phishing email bypass filter enable qr scanning

The quishing term variant admins search.

image only phishing email qr code users scanned phone defence

The phone angle variant stressing the unmanaged device.

Compatibility: Cloud email gateway QR and OCR features, Defender policies, mobile device guidance.

Edge cases to check:

• Attackers rotate the QR target through redirectors; extract and block the final domain as well as the landing page.
• Some legitimate services send image heavy mail; audit mode data tells you which senders need exceptions before enforcement.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_ZJcDU9WUXbqixaTyFuwFsg