Suspicious Office 365 app authorization (OAuth) link

name: "Suspicious Office 365 app authorization (OAuth) link"
description: |
  Message contains a suspicious Office 365 app authorization (OAuth) link. The app may be compromised or 
  was stood up for malicious purposes. Once the app has been authorized, the attacker will have 
  read or write permissions to the user's Office 365 account.
references:
  - "https://info.phishlabs.com/blog/office-365-phishing-uses-malicious-app-persist-password-reset"
type: "rule"
severity: "high"
source: |
  type.inbound
  and (
    // links in email body
    any([body.links, body.current_thread.links],
        any(.,
            (
              .href_url.domain.domain == 'login.microsoftonline.com'
              or strings.icontains(.href_url.query_params,
                                   "login.microsoftonline.com"
              )
            )
            and (
              strings.ilike(.href_url.query_params,
                            '*offline_access*',
                            '*.readwrite*',
                            '*.read*',
                            '*ctx=*',
                            '*prompt=none*'
              )
              or (
                (
                  strings.icontains(.href_url.path, '/common/reprocess')
                  or strings.icontains(.href_url.query_params,
                                       "/common/reprocess"
                  )
                )
                and strings.icontains(.href_url.query_params, 'ctx=')
                and strings.icontains(.href_url.query_params, 'sessionId=')
              )
            )
        )
    )
    // links in PDF, HTML, DOCX and PPTX attachments
    or any(filter(attachments, .file_type in ("pdf", "html", "docx", "pptx")),
           any(file.explode(.),
               any(.scan.url.urls,
                   .domain.domain == 'login.microsoftonline.com'
                   and (
                     strings.ilike(.query_params,
                                   '*offline_access*',
                                   '*.readwrite*',
                                   '*.read*',
                                   '*ctx=*',
                                   '*prompt=none*'
                     )
                     or (
                       strings.icontains(.path, '/common/reprocess')
                       and strings.icontains(.query_params, 'ctx=')
                       and strings.icontains(.query_params, 'sessionId=')
                     )
                   )
               )
           )
    )
    or any(attachments,
           (
             .file_type == "ics"
             or .file_extension == "ics"
             or .content_type in ("application/ics", "text/calendar")
           )
           //
           // 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 any(beta.file.parse_ics(.).events,
                   any(.links,
                       .href_url.domain.domain == 'login.microsoftonline.com'
                       and (
                         strings.ilike(.href_url.query_params,
                                       '*offline_access*',
                                       '*.readwrite*',
                                       '*.read*',
                                       '*ctx=*',
                                       '*prompt=none*'
                         )
                         or (
                           strings.icontains(.href_url.path, '/common/reprocess')
                           and strings.icontains(.href_url.query_params, 'ctx=')
                           and strings.icontains(.href_url.query_params,
                                                 'sessionId='
                           )
                         )
                       )
                   )
           )
    )
  )

attack_types:
  - "Credential Phishing"
detection_methods:
  - "URL analysis"
id: "13a8c430-3e62-5c8f-86b5-3722599bead4"