Detection rules › Sublime MQL
Service abuse: Adobe Sign notification from an unsolicited reply-to address
Identifies messages appearing to come from Adobe Sign signature notifications that contain a reply-to address not previously seen in organizational communications. This tactic exploits trust in legitimate Adobe services while attempting to establish unauthorized communication channels.
Threat classification
Sublime's own taxonomy (not MITRE ATT&CK).
| Category | Values |
|---|---|
| Attack types | BEC/Fraud, Callback Phishing, Spam |
| Tactics and techniques | Social engineering, Impersonation: Brand |
Event coverage
| Message attribute |
|---|
| headers.auth_summary |
| sender.email |
| subject |
| type |
Rule body MQL
type.inbound
// Legitimate Adobe Sign sending infratructure
and sender.email.email == "adobesign@adobesign.com"
and headers.auth_summary.spf.pass
and headers.auth_summary.dmarc.pass
and strings.icontains(subject.subject, 'signature requested')
//
// 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
//
// reply-to address has never sent an email to the org
and beta.profile.by_reply_to().prevalence == "new"
// reply-to email address has never been sent an email by the org
and not beta.profile.by_reply_to().solicited
// do not match if the reply_to address has been observed as a reply_to address
// of a message that has been classified as benign
and not beta.profile.by_reply_to().any_messages_benign
Detection logic
Scope: inbound message.
Identifies messages appearing to come from Adobe Sign signature notifications that contain a reply-to address not previously seen in organizational communications. This tactic exploits trust in legitimate Adobe services while attempting to establish unauthorized communication channels.
- inbound message
- sender.email.email is 'adobesign@adobesign.com'
- headers.auth_summary.spf.pass
- headers.auth_summary.dmarc.pass
- subject.subject contains 'signature requested'
- beta.profile.by_reply_to().prevalence is 'new'
not:
- beta.profile.by_reply_to().solicited
not:
- beta.profile.by_reply_to().any_messages_benign
Inspects: headers.auth_summary.dmarc.pass, headers.auth_summary.spf.pass, sender.email.email, subject.subject, type.inbound. Sensors: beta.profile.by_reply_to, strings.icontains.
Indicators matched (2)
| Field | Match | Value |
|---|---|---|
sender.email.email | equals | adobesign@adobesign.com |
strings.icontains | substring | signature requested |