Update whitespace stuffing regex and generic document sharing thread exclusion#4556
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… account phishing Add class-attributed div-br pattern to catch Outlook elementToProof whitespace stuffing variant. Add self-sender BCC carve-out to generic document sharing rule so compromised accounts replaying real threads aren't blanket-excluded. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Test Rules Sync - ExcludedThis PR contains rules that use The |
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Description
Two updates to improve detection of compromised-account phishing that uses real thread history and whitespace padding:
evasion_excessive_image_padding_cred_theft.yml— Add class-attributed div-br regex pattern to catch OutlookelementToProofwhitespace stuffing variant. The existing regex only matches bare<div>or<div style=...>(style as first attribute), missing the common Outlook pattern<div class="elementToProof" style="..."><br></div>repeated 100+ times.credential_phishing_generic_document_sharing.yml— Add self-sender BCC carve-out to theprevious_threadsexclusion. Compromised accounts replay real thread history to bypass this check. The carve-out requires all three:length(recipients.to) == 1,length(recipients.cc) == 0, andsender.email.email == recipients.to[0].email.email.Associated samples
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