AegisAI Perspectives · 133
AI startups stop fake founder and investor emails with DMARC, lookalike warnings, an outside sender banner and a call-back rule set before news is out.
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An AI startup stops these emails by setting its checks before the funding news goes out, because public role titles and email addresses can be harvested for impersonation attempts1. The checks: DMARC on every domain you own, lookalike domain warnings, an outside sender banner, and a written call-back rule.
AegisAI investigates every email for what it is trying to do, and removes the ones that fail from every mailbox they reached20. If you run IT for an AI startup of 20 to 500 people on Microsoft 365 or Google Workspace, with a lean IT or security team and no SOC, this is the list to finish before the press release. The product side is on the inbound email security page. CEO fraud in general, with the full call-back procedure, is in how email security stops CEO fraud and payroll diversion. AI-written lures are in the best email security for AI-generated spear phishing. This page covers the weeks around the announcement.
The announcement publishes what an impersonator needs: the founders' names, the investors' names, the size of the round and the new hires. Role titles and email addresses that are public can be harvested for impersonation attempts. A new hire has never seen a real email from the CEO, so a fake one has nothing to be compared with.
Scammers impersonate employees or managers of small businesses to trick staff into sharing sensitive information, transferring funds, or granting access to business systems3. The losses are large: the FBI IC3 lists Business Email Compromise losses of $2,770,151,146 for 202410.
Put the announcement date in the security calendar and finish the checks below a week before it.
Short on time? Watch the explainer, or book a demo.
They are two forms of Business Email Compromise, where a criminal uses email to impersonate an executive or employee to request fraudulent payments or payroll information4.
Write both asks down as examples and show them to every new hire in their first week.
Do these in order, about one week before the news is public.
Publish SPF and DKIM for every sending domain, then allow 48 hours before you set up DMARC14.
Start DMARC with the policy option set to none, as Google recommends, and read the reports for unknown senders.
Move to a p=reject DMARC policy for all custom domains and subdomains, testing along the way so good mail is not rejected18.
For parked domains you own but never send from, set DMARC records that say no email should ever come from them.
In Google Workspace, turn on lookalike domain protection against domains visually similar to yours15. In Microsoft 365, check the spoof intelligence, first contact safety tip and unauthenticated sender indicators that every cloud mailbox already gets17.
Add an email banner that says when a message comes from outside your organization6.
Write a verification procedure for financial and information requests, such as a change of bank account details2.
Make the rule concrete: any request for a payment or personnel records is confirmed by phone before anyone acts7, and any change to account details is checked on a second channel8.
Run steps 1 to 4 first, because DMARC needs days of reports before you can move to reject.
DMARC protects your exact domain. It says nothing about a domain the attacker owns. Impersonation can pass email authentication if the attacker created a lookalike domain and published valid DNS records.
AegisAI research found that among AI spear phishing emails that evaded filters, 72.6 percent passed DMARC25. A pass tells you which domain sent the message. It does not tell you whether the request inside it is real.
So the fake investor ask needs a second test: the request itself. Who is asking, what changes, where the reply goes. Treat a DMARC pass as one signal and keep the call-back rule for every money request.
| Check | Built-in settings and written rules | AegisAI |
|---|---|---|
| Mail that forges your exact domain | DMARC at p=reject | No edge. DMARC is a DNS setting you own |
| Lookalike domain with valid records | Lookalike warning in Google Workspace; it can still pass authentication | Does not rely on authentication, because it passes23 |
| Fake founder ask with no link or file | Outside sender banner and the written procedure | Judges the request itself, with no link or file needed |
| Fake investor wire change | Call-back on a known number | Reads the sender's history, the change asked for and where the reply goes |
| Where it acts | DNS and mail settings act as mail arrives | No edge before delivery. It reads mail through the API after delivery |
The first and last rows give no edge: DMARC stays your job, and the review happens after delivery. Fill one copy of this table for your own tenant before the announcement.
It reads the thread the way an analyst would: the sender’s history, the change being asked for, and where the reply actually goes22. Catches fake executives, vendors and payment requests, even with no link or file to scan. It reads mail through the Microsoft 365 or Google Workspace API after delivery11. Runs in monitoring mode first9.
Illustrative example, figures are fictional: Larkfield Labs (fictional), a 60-person AI startup on Google Workspace, announces its seed round on a Tuesday. On Thursday a new hire gets an email signed with the CEO's name from a personal address, asking for gift cards for a team event. The new hire checks the written rule, sees the CEO never asks for gift cards by email, and reports it. On Friday the finance lead gets an email from a domain one letter off the lead investor's firm, asking to confirm wire details for closing. The domain has valid DNS records, so authentication passes, but the lookalike warning flags it. The finance lead calls the investor on the number already on file. The investor sent nothing, and the email is deleted from every inbox.
Walk your own team through one fake founder ask and one fake investor ask like these before the news goes out.
Track three numbers for the 30 days after the announcement, each from a log you already have.
To see what your current settings let through on your own mail, start a monitoring-mode trial. Put the three numbers side by side on day 30 and fix the weakest check first.
They set DMARC at p=reject, lookalike domain warnings, an outside sender banner and a call-back rule before the news goes out. AegisAI adds a review of the request itself: it reads the sender's history, the change asked for and where the reply goes.
Not on its own. DMARC protects your exact domain, but a lookalike domain with valid DNS records passes email authentication. Pair it with lookalike warnings and a call-back rule.
Before the announcement. Public role titles and email addresses can be harvested for impersonation, and Google says to allow 48 hours after SPF and DKIM before setting up DMARC.
Tell them how leaders will and will not contact them. Tell them that urgent payment requests, often via gift cards, are a warning sign, and that payment requests are confirmed by phone.
Yes, at a basic level. Microsoft 365 gives every cloud mailbox spoof intelligence and a first contact safety tip. Google Workspace has a lookalike domain setting. Turn both on before the announcement.
