Medium Severity
Callback Phishing: Branded invoice from sender/reply-to domain less than 30 days old
Description
This rule checks for invoicing content from a sender, reply-to domain or return-path domain less than 30d old. It also checks the body or the OCR'd screenshot for key words commonly abused in fraudulent invoicing attacks.
References
No references.
Sublime Security
Created Nov 20th, 2023 • Last updated Apr 25th, 2024
Feed Source
Sublime Core Feed
Source
type.inbound
// reply to domain that's less than 30d old and doesn't match the sender
and (
(
length(headers.reply_to) > 0
and all(headers.reply_to,
network.whois(.email.domain).days_old <= 30
and .email.email != sender.email.email
)
)
// or the return path or sender domain is less than 30d old
or network.whois(headers.return_path.domain).days_old <= 30
or network.whois(sender.email.domain).days_old <= 30
)
// invoicing with high confidence
and any(ml.nlu_classifier(body.current_thread.text).tags,
.name == "invoice" and .confidence == "high"
)
// commonly abused brands in body
and (
strings.ilike(body.current_thread.text,
"*mcafee*",
"*norton*",
"*geek squad*",
"*paypal*",
"*ebay*",
"*symantec*",
"*best buy*",
"*lifelock*",
"*virus*"
)
// commonly abused brand logo
or any(ml.logo_detect(beta.message_screenshot()).brands,
.name in ("PayPal", "Norton", "GeekSquad", "Ebay")
)
// check message screenshot ocr for commonly abused brands
or any(file.explode(beta.message_screenshot()),
1 of (
strings.icontains(.scan.ocr.raw, "geek squad"),
strings.icontains(.scan.ocr.raw, "lifelock"),
strings.icontains(.scan.ocr.raw, "best buy"),
strings.icontains(.scan.ocr.raw, "mcafee"),
strings.icontains(.scan.ocr.raw, "norton"),
strings.icontains(.scan.ocr.raw, "ebay"),
strings.icontains(.scan.ocr.raw, "paypal"),
strings.icontains(.scan.ocr.raw, "virus"),
)
)
)
// phone number regex
and regex.icontains(body.current_thread.text,
'\+?(\d{1}.)?\(?\d{3}?\)?.\d{3}.?\d{4}'
)
and not profile.by_sender().solicited
and not profile.by_sender().any_false_positives
Playground
Test against your own EMLs or sample data.