Detection rules › Sublime MQL
Generic service abuse from newly registered domain
Detects messages from services that write the true sender to the reply-to field, where the sender has no prior legitimate message history and is newly registered. Indicative of service abuse.
Threat classification
Sublime's own taxonomy (not MITRE ATT&CK).
| Category | Values |
|---|---|
| Attack types | BEC/Fraud, Callback Phishing, Credential Phishing |
| Tactics and techniques | Evasion, Social engineering |
Event coverage
| Message attribute |
|---|
| headers (collection) |
| headers.reply_to (collection) |
| sender.email |
| type |
Rule body MQL
type.inbound
and any(headers.reply_to, network.whois(.email.domain).days_old < 30)
and sender.email.domain.domain in $replyto_service_domains
//
// This rule makes use of a beta feature and is subject to change without notice
// using the beta feature in custom rules is not suggested until it has been formally released
//
and not beta.profile.by_reply_to().solicited
and not beta.profile.by_reply_to().any_messages_benign
Detection logic
Scope: inbound message.
Detects messages from services that write the true sender to the reply-to field, where the sender has no prior legitimate message history and is newly registered. Indicative of service abuse.
- inbound message
any of
headers.reply_towhere:- network.whois(.email.domain).days_old < 30
- sender.email.domain.domain in $replyto_service_domains
not:
- beta.profile.by_reply_to().solicited
not:
- beta.profile.by_reply_to().any_messages_benign
Inspects: headers.reply_to, headers.reply_to[].email.domain, sender.email.domain.domain, type.inbound. Sensors: beta.profile.by_reply_to, network.whois. Reference lists: $replyto_service_domains.