Detection rules › Sublime MQL

Service abuse: Recruiting with suspicious language patterns from legitimate platforms

Severity
medium
Type
rule
Source
github.com/sublime-security/sublime-rules

Detects suspicious recruiting messages from legitimate services like Salesforce, LADesk, or AWS Apps with unusually long sender email addresses and recruiting-specific language patterns that may indicate abuse of trusted platforms for social engineering.

Threat classification

Sublime's own taxonomy (not MITRE ATT&CK).

CategoryValues
Attack typesBEC/Fraud
Tactics and techniquesSocial engineering

Event coverage

Rule body MQL

type.inbound
and length(sender.email.email) >= 50
and sender.email.domain.root_domain in (
  "salesforce.com",
  "ladesk.com",
  "awsapps.com"
)
and (
  (
    any(ml.nlu_classifier(body.current_thread.text).topics,
        .name in ("B2B Cold Outreach", "Professional and Career Development")
    )
    and not any(ml.nlu_classifier(body.current_thread.text).topics,
                .name == "Reminders and Notifications" and .confidence == "high"
    )
  )
  or 2 of (
    strings.icontains(body.current_thread.text, "profile caught my attention"),
    strings.icontains(body.current_thread.text, "recruiting top talent"),
    strings.icontains(body.current_thread.text, "talent acquisition team"),
    strings.icontains(body.current_thread.text,
                      "experience seems highly relevant"
    ),
    strings.icontains(body.current_thread.text, "expling this opptunity"),
    strings.icontains(body.current_thread.text, "your professional profile"),
    strings.icontains(body.current_thread.text, "a pivotal hire"),
    strings.icontains(body.current_thread.text, "a key hire"),
    strings.icontains(body.current_thread.text, "schedule a time")
  )
)

Detection logic

Scope: inbound message.

Detects suspicious recruiting messages from legitimate services like Salesforce, LADesk, or AWS Apps with unusually long sender email addresses and recruiting-specific language patterns that may indicate abuse of trusted platforms for social engineering.

  1. inbound message
  2. length(sender.email.email) ≥ 50
  3. sender.email.domain.root_domain in ('salesforce.com', 'ladesk.com', 'awsapps.com')
  4. any of:
    • all of:
      • any of ml.nlu_classifier(body.current_thread.text).topics where:
        • .name in ('B2B Cold Outreach', 'Professional and Career Development')
      • not:
        • any of ml.nlu_classifier(body.current_thread.text).topics where all hold:
          • .name is 'Reminders and Notifications'
          • .confidence is 'high'
    • at least 2 of 9: body.current_thread.text contains any of 9 patterns
      • profile caught my attention
      • recruiting top talent
      • talent acquisition team
      • experience seems highly relevant
      • expling this opptunity
      • your professional profile
      • a pivotal hire
      • a key hire
      • schedule a time

Inspects: body.current_thread.text, sender.email.domain.root_domain, sender.email.email, type.inbound. Sensors: ml.nlu_classifier, strings.icontains.

Indicators matched (16)

FieldMatchValue
sender.email.domain.root_domainmembersalesforce.com
sender.email.domain.root_domainmemberladesk.com
sender.email.domain.root_domainmemberawsapps.com
ml.nlu_classifier(body.current_thread.text).topics[].namememberB2B Cold Outreach
ml.nlu_classifier(body.current_thread.text).topics[].namememberProfessional and Career Development
ml.nlu_classifier(body.current_thread.text).topics[].nameequalsReminders and Notifications
ml.nlu_classifier(body.current_thread.text).topics[].confidenceequalshigh
strings.icontainssubstringprofile caught my attention
strings.icontainssubstringrecruiting top talent
strings.icontainssubstringtalent acquisition team
strings.icontainssubstringexperience seems highly relevant
strings.icontainssubstringexpling this opptunity
4 more
strings.icontainssubstringyour professional profile
strings.icontainssubstringa pivotal hire
strings.icontainssubstringa key hire
strings.icontainssubstringschedule a time