sublimelowRule

Spam: Firebase password reset from suspicious sender

Detects Firebase password reset messages from suspicious or new senders that may be attempting to abuse the Firebase authentication service.

MITRE ATT&CK

T1566 T1566.001 T1566.002 T1598 T1036 T1027

defense-evasioninitial-access

Detection Query

type.inbound
and sender.email.domain.root_domain == "firebaseapp.com"
and length(filter(body.links,
                  .href_url.domain.root_domain not in ("aka.ms")
                  and .href_url.path is not null
           )
) == 1
and any(body.links,
        .href_url.domain.domain == sender.email.domain.domain
        and .href_url.path == "/__/auth/action"
        and any(.href_url.query_params_decoded["mode"], . == "resetPassword")
)
and (
  (
    not profile.by_sender().solicited
    and profile.by_sender().prevalence == "new"
  )
  or (
    profile.by_sender().any_messages_malicious_or_spam
    and not profile.by_sender().any_messages_benign
  )
  or not headers.auth_summary.dmarc.pass
)

Data Sources

Email MessagesEmail HeadersEmail Attachments

Platforms

Tags

Attack surface reduction

Raw Content

name: "Spam: Firebase password reset from suspicious sender"
description: "Detects Firebase password reset messages from suspicious or new senders that may be attempting to abuse the Firebase authentication service."
type: "rule"
severity: "low"
source: |
  type.inbound
  and sender.email.domain.root_domain == "firebaseapp.com"
  and length(filter(body.links,
                    .href_url.domain.root_domain not in ("aka.ms")
                    and .href_url.path is not null
             )
  ) == 1
  and any(body.links,
          .href_url.domain.domain == sender.email.domain.domain
          and .href_url.path == "/__/auth/action"
          and any(.href_url.query_params_decoded["mode"], . == "resetPassword")
  )
  and (
    (
      not profile.by_sender().solicited
      and profile.by_sender().prevalence == "new"
    )
    or (
      profile.by_sender().any_messages_malicious_or_spam
      and not profile.by_sender().any_messages_benign
    )
    or not headers.auth_summary.dmarc.pass
  )
tags:
  - "Attack surface reduction"
attack_types:
  - "Credential Phishing"
  - "Spam"
tactics_and_techniques:
  - "Evasion"
  - "Social engineering"
detection_methods:
  - "Header analysis"
  - "Sender analysis"
  - "URL analysis"
id: "a2f673a9-11e5-51c5-ab1e-f374a9662294"