Medium Severity

Evasion: Hidden content divs from freemail sender

Labels

Credential Phishing
Evasion
Free email provider
HTML analysis
Content analysis
Sender analysis

Description

Detects inbound messages from freemail senders containing multiple hidden HTML div elements with specific styling properties (display:none, opacity:0, zero dimensions) that are commonly used to evade content filtering and detection systems.

References

No references.

Sublime Security
Created Jun 17th, 2026 • Last updated Jun 17th, 2026
Feed Source
Sublime Core Feed
Source
GitHub
type.inbound
and sender.email.domain.root_domain in $free_email_providers
and strings.count(body.html.raw,
                  '<div style="display:none;opacity:0;width:0;height:0;overflow:hidden" aria-hidden="true">'
) >= 3
MQL Rule Console
•Docs•Learning Labs

Playground

Test against your own EMLs or sample data.

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