Medium Severity

Service abuse: Microsoft with suspicious indicators in subject

Description

Detects messages impersonating Microsoft account verification that contain suspicious indicators in the subject line, including phone numbers, monetary amounts, suspicious domains, explicit content, or lengthy action-oriented phrases.

References

No references.

Sublime Security
Created May 7th, 2026 • Last updated May 7th, 2026
Source
type.inbound
//
//  Warning: This rule contains sexually explicit keywords
//
and sender.email.domain.root_domain == "microsoftonline.com"
and strings.icontains(subject.subject, 'account email verification code')
and (
  // phone number regex
  regex.icontains(subject.base,
                  '\+?(?:[ilo0-9]{1}.)?\(?[ilo0-9]{3}?\)?.[ilo0-9]{3}.?[ilo0-9]{4}',
                  '\+?(?:[ilo0-9]{1,2})?\s?\(?\d{3}\)?[\s\.\-⋅]{0,5}[ilo0-9]{3}[\s\.\-⋅]{0,5}[ilo0-9]{4}'
  )
  // dollar amounts
  or regex.icontains(subject.base, '(?:USD|\$)\s?\d')
  or regex.icontains(subject.base, '\d+\.\d{2}\s?(?:USD|usd)')
  // suspicious TLDs
  or regex.icontains(subject.base,
                     '\.(?:ac\.th|biz\.id|co\.(?:cl|id|za)|com\.(?:ge|py)|my\.id|ne\.jp|net\.ms|nom\.za|web\.id|accountants|am|app|ar|army|beauty|best|bet|bio|biz|bond|cam|cc|cf|cfd|chat|cl|click|cloud|club|cm|company|consulting|country|cricket|cyou|date|dev|digital|directory|domains|download|enterprises|es|expert|fashion|finance|fit|foo|free|fun|ga|gdn|gf|gq|gu|help|i2p|icu|il|ing|ink|ir|jetzt|kim|kz|lat|life|limited|link|live|loan|lol|ltd|ly|me|meme|men|ml|mom|monster|mov|mq|one|online|ooo|party|photos|pictures|pizza|press|pro|pub|pw|racing|re|ren|rest|review|ro|rsvp|ru|run|sale|sbs|science|shop|site|so|social|solutions|space|store|stream|su|sx|tech|tk|today|tokyo|top|trade|tt|ua|uno|us|vip|vu|wang|website|win|work|works|world|ws|xin|xyz|zip|zone)\b'
  )
  // dating/spam/explicit content lures
  or regex.icontains(strings.replace_confusables(subject.base),
                     '(?:\bs\s?e\s?x\b|horny|hook.?up|private room|wanna meet|wants to meet|naked|porn|webcam|nudes?|sexting|erotic|kinky|seduce|adult community|cam shows|local (?:girls?|women|single)|bed partner)'
  )
  // action verbs + length
  or (
    strings.count(subject.base, " ") > 8
    and regex.icontains(strings.replace_confusables(subject.base),
                        '(?:call|dial|speak to|contact \d|to (?:stop|void|reverse|confirm|secure|verify|unfreeze))'
    )
  )
)
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