sublimehighRule

Attachment: Office file contains OLE relationship to credential phishing page

Office file OLE relationship link is a credential page, or contains credential phishing language.

MITRE ATT&CK

T1566 T1566.001 T1566.002 T1598 T1036 T1027

defense-evasioninitial-access

Detection Query

type.inbound
and any(attachments,
        (
          .file_extension in~ $file_extensions_macros
          or (
            .file_extension is null
            and .file_type == "unknown"
            and .content_type == "application/octet-stream"
            and .size < 100000000
          )
        )
        and length(file.oletools(.).relationships) < 500
        and any(file.oletools(.).relationships,
                (
                  any(ml.nlu_classifier(ml.link_analysis(.target_url).final_dom.display_text
                      ).intents,
                      .name == "cred_theft"
                      and .confidence in ("medium", "high")
                  )
                  and .target_url.domain.root_domain not in (
                    "google.com",
                    "goo.gl"
                  )
                  and ml.link_analysis(.target_url).effective_url.domain.domain != "login.microsoftonline.com"
                )
                or ml.link_analysis(.target_url).credphish.disposition == "phishing"
        )
)
and (
  (
    profile.by_sender().prevalence in ("new", "outlier")
    and not profile.by_sender().solicited
  )
  or (
    profile.by_sender().any_messages_malicious_or_spam
    and not profile.by_sender().any_messages_benign
  )
)

Data Sources

Email MessagesEmail HeadersEmail Attachments

Platforms

Raw Content

name: "Attachment: Office file contains OLE relationship to credential phishing page"
description: |
  Office file OLE relationship link is a credential page, or contains credential phishing language.
type: "rule"
severity: "high"
source: |
  type.inbound
  and any(attachments,
          (
            .file_extension in~ $file_extensions_macros
            or (
              .file_extension is null
              and .file_type == "unknown"
              and .content_type == "application/octet-stream"
              and .size < 100000000
            )
          )
          and length(file.oletools(.).relationships) < 500
          and any(file.oletools(.).relationships,
                  (
                    any(ml.nlu_classifier(ml.link_analysis(.target_url).final_dom.display_text
                        ).intents,
                        .name == "cred_theft"
                        and .confidence in ("medium", "high")
                    )
                    and .target_url.domain.root_domain not in (
                      "google.com",
                      "goo.gl"
                    )
                    and ml.link_analysis(.target_url).effective_url.domain.domain != "login.microsoftonline.com"
                  )
                  or ml.link_analysis(.target_url).credphish.disposition == "phishing"
          )
  )
  and (
    (
      profile.by_sender().prevalence in ("new", "outlier")
      and not profile.by_sender().solicited
    )
    or (
      profile.by_sender().any_messages_malicious_or_spam
      and not profile.by_sender().any_messages_benign
    )
  )
attack_types:
  - "Credential Phishing"
tactics_and_techniques:
  - "Evasion"
  - "Social engineering"
detection_methods:
  - "File analysis"
  - "HTML analysis"
  - "Natural Language Understanding"
  - "OLE analysis"
  - "URL analysis"
id: "d55793d0-865e-53c4-ae51-f1b0fec50ec6"