Sublime Security medium experimental mql
COVID-19 themed fraud with sender and reply-to mismatch or compensation award
Detects potential COVID-19 themed BEC/Fraud scams by analyzing text within the email body for mentions of COVID-19 assistance, compensation, or awards from mismatched senders and other suspicious language.
Detection Logic
type.inbound
// mismatched sender (From) and Reply-to + freemail
and (
length(headers.reply_to) > 0
and all(headers.reply_to,
.email.domain.root_domain != sender.email.domain.root_domain
and .email.domain.root_domain in $free_email_providers
)
)
// use of honorific
and regex.icontains(body.current_thread.text,
'(?:Mr
| Mrs
| Ms
| Miss
| Dr
| Prof
| Sir
| Lady
| Rev)\.?[ \t]+',
'Dear Sir'
)
// mention of covid or an international organization
and regex.icontains(body.current_thread.text,
'international (court of justice
| monetary fund)',
'united nations',
'western union',
'world bank',
'world health organization',
'interpol',
'treasury',
'\bFEMA\b',
'\bIMF\b'
)
// and mention of covid in subject or body
and (
regex.icontains(subject.subject, 'covid(.{0,5}19)?\b')
or regex.icontains(body.current_thread.text, 'covid(.{0,5}19)?\b')
)
// Check for compensation or award related language
and (
2 of (
any(ml.nlu_classifier(body.current_thread.text).entities,
.name == "urgency"
),
any(ml.nlu_classifier(body.current_thread.text).entities,
.name == "request"
),
any(ml.nlu_classifier(body.current_thread.text).entities,
.name == "financial"
)
)
or regex.icontains(subject.subject,
'compensation.{0,20}(award
| fund)',
'covid.{0,20}(compensation
| award)',
'selected.{0,30}(compensation
| award)',
'claim your award',
'reference no'
)
or regex.icontains(body.current_thread.text,
'compensation.{0,20}(award
| fund)',
'covid.{0,20}(compensation
| award)',
'selected.{0,30}(compensation
| award)',
'claim your award',
'reference no\W\s*[^\s]*cov(?:id)?(?:.{0,5}19)?\b'
)
)
// negate highly trusted sender domains unless they fail DMARC authentication
and (
(
sender.email.domain.root_domain in $high_trust_sender_root_domains
and not headers.auth_summary.dmarc.pass
)
or sender.email.domain.root_domain not in $high_trust_sender_root_domains
) Field Validations
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