Detection Method: HTML analysis

HTML analysis looks at the HTML code in emails, web pages, or attachments to spot potentially malicious elements or deceptive structures. It examines both what’s visible and hidden in the HTML to uncover tactics often used in phishing or malware attacks.
HTML analysis can help you detect:
  • Hidden scripts or iframes that might run harmful code
  • Obfuscated JavaScript designed to avoid detection
  • Misleading hyperlinks where the displayed text doesn’t match the real URL
  • Forms made to steal credentials or sensitive data
  • Suspicious HTML comments with hidden instructions
  • CSS tricks used to hide malicious content
For example, phishing emails often use HTML to replicate trusted login pages. HTML analysis can catch the hidden forms and scripts trying to steal your credentials.
Blog Posts
Talking phish over turkey · Blog · Sublime Security
Talking phish over turkey · Blog · Sublime Security
Living Off the Land: Credential Phishing via Docusign abuse · Blog · Sublime Security
Living Off the Land: Credential Phishing via Docusign abuse · Blog · Sublime Security
Call Me Maybe? The Rise of Callback Phishing Emails · Blog · Sublime Security
Call Me Maybe? The Rise of Callback Phishing Emails · Blog · Sublime Security
Attack Types (6):
BEC/Fraud
Credential Phishing
Spam
Malware/Ransomware
Callback Phishing
Extortion
Tactics & Techniques (21):
Evasion
Impersonation: Brand
Social engineering
Impersonation: VIP
Lookalike domain
Free subdomain host
Credential Phishing
HTML smuggling
Scripting
Encryption
Free email provider
Open redirect
Image as content
Free file host
HTML injection
Impersonation: Employee
OneNote
PDF
Exploit
Out of band pivot
ISO
Rule Name & Severity
Last Updated
Author
Types, Tactics & Capabilities
Service abuse: HungerRush domain with SendGrid tracking targeting ProtonMail
15h ago
Mar 4th, 2026
Sublime Security
BEC/Fraud
Evasion
Sender analysis
HTML analysis
Content analysis
/feeds/core/detection-rules/service-abuse-hungerrush-domain-with-sendgrid-tracking-targeting-protonmail-73f62e74
Link: Apple App Store link to apps impersonating AI adveristing
20h ago
Mar 4th, 2026
Sublime Security
Credential Phishing
Impersonation: Brand
Content analysis
URL analysis
HTML analysis
/feeds/core/detection-rules/link-apple-app-store-link-to-apps-impersonating-ai-adveristing-19b556e6
Brand impersonation: Zoom via HTML styling
6d ago
Feb 27th, 2026
Sublime Security
Credential Phishing
Impersonation: Brand
Social engineering
Content analysis
HTML analysis
/feeds/core/detection-rules/brand-impersonation-zoom-via-html-styling-b717920d
Link: Credential theft with invisible Unicode character in page title from unsolicited sender
20d ago
Feb 13th, 2026
Sublime Security
Credential Phishing
Evasion
Social engineering
Natural Language Understanding
Content analysis
HTML analysis
URL analysis
URL screenshot
/feeds/core/detection-rules/link-credential-theft-with-invisible-unicode-character-in-page-title-from-unsolicited-sender-5fe14d53
Brand impersonation: Microsoft Teams invitation
27d ago
Feb 6th, 2026
Sublime Security
Credential Phishing
Impersonation: Brand
Social engineering
Content analysis
Header analysis
HTML analysis
URL analysis
/feeds/core/detection-rules/brand-impersonation-microsoft-teams-invitation-46410ad8
Service abuse: Apple TestFlight with suspicious developer reference
27d ago
Feb 6th, 2026
Sublime Security
Spam
Social engineering
Content analysis
HTML analysis
Natural Language Understanding
Sender analysis
URL analysis
/feeds/core/detection-rules/service-abuse-apple-testflight-with-suspicious-developer-reference-e7ea0ee0
Link: Common hidden directory observed
30d ago
Feb 3rd, 2026
Sublime Security
Credential Phishing
Evasion
URL analysis
HTML analysis
/feeds/core/detection-rules/link-common-hidden-directory-observed-9f316da6
Service abuse: Trello board invitation with VIP impersonation
30d ago
Feb 3rd, 2026
Sublime Security
Credential Phishing
Impersonation: VIP
Social engineering
Content analysis
Header analysis
HTML analysis
Sender analysis
/feeds/core/detection-rules/service-abuse-trello-board-invitation-with-vip-impersonation-fedfc94b
Brand impersonation: Aramco
1mo ago
Jan 28th, 2026
Sublime Security
BEC/Fraud
Impersonation: Brand
Lookalike domain
Social engineering
Content analysis
Header analysis
HTML analysis
Natural Language Understanding
Sender analysis
/feeds/core/detection-rules/brand-impersonation-aramco-96e87699
Brand impersonation: File sharing notification with template artifacts
1mo ago
Jan 23rd, 2026
Sublime Security
Credential Phishing
Impersonation: Brand
Social engineering
Evasion
HTML analysis
Computer Vision
Content analysis
Header analysis
/feeds/core/detection-rules/brand-impersonation-file-sharing-notification-with-template-artifacts-37d89611
Link: Tycoon2FA phishing kit (non-exhaustive)
1mo ago
Jan 23rd, 2026
Sublime Security
Credential Phishing
Free subdomain host
Evasion
Credential Phishing
URL analysis
HTML analysis
Content analysis
/feeds/core/detection-rules/link-tycoon2fa-phishing-kit-non-exhaustive-a070d4e2
Spam: Commonly observed formatting of unauthorized free giveaways
1mo ago
Jan 14th, 2026
Sublime Security
Spam
Impersonation: Brand
Social engineering
Content analysis
HTML analysis
Sender analysis
URL analysis
/feeds/core/detection-rules/spam-commonly-observed-formatting-of-unauthorized-free-giveaways-8bc49fa3
Attachment: HTML smuggling with concatenation obfuscation
1mo ago
Jan 12th, 2026
@vector_sec
Credential Phishing
Malware/Ransomware
Evasion
HTML smuggling
Scripting
Archive analysis
Content analysis
File analysis
HTML analysis
/feeds/core/detection-rules/attachment-html-smuggling-with-concatenation-obfuscation-108ab346
Attachment: HTML smuggling with decimal encoding
1mo ago
Jan 12th, 2026
Sublime Security
Credential Phishing
Malware/Ransomware
Evasion
HTML smuggling
Scripting
Archive analysis
Content analysis
File analysis
HTML analysis
/feeds/core/detection-rules/attachment-html-smuggling-with-decimal-encoding-f99213c4
Attachment: HTML smuggling with eval and atob
1mo ago
Jan 12th, 2026
Sublime Security
Credential Phishing
Malware/Ransomware
Evasion
HTML smuggling
Scripting
Archive analysis
Content analysis
File analysis
HTML analysis
Javascript analysis
/feeds/core/detection-rules/attachment-html-smuggling-with-eval-and-atob-9f521ca2
Attachment: HTML smuggling with base64 encoded JavaScript function
1mo ago
Jan 12th, 2026
Sublime Security
Credential Phishing
Malware/Ransomware
HTML smuggling
Scripting
Archive analysis
Content analysis
File analysis
HTML analysis
Javascript analysis
/feeds/core/detection-rules/attachment-html-smuggling-with-base64-encoded-javascript-function-4e8a12ec
Attachment: HTML smuggling with excessive line break obfuscation
1mo ago
Jan 12th, 2026
Sublime Security
Credential Phishing
Malware/Ransomware
Encryption
Evasion
HTML smuggling
Scripting
Archive analysis
Content analysis
File analysis
HTML analysis
Javascript analysis
/feeds/core/detection-rules/attachment-html-smuggling-with-excessive-line-break-obfuscation-7e901440
Attachment: HTML smuggling with RC4 decryption
1mo ago
Jan 12th, 2026
Sublime Security
Credential Phishing
Malware/Ransomware
Encryption
Evasion
HTML smuggling
Scripting
Archive analysis
Content analysis
File analysis
HTML analysis
Javascript analysis
/feeds/core/detection-rules/attachment-html-smuggling-with-rc4-decryption-3a46d765
Attachment: HTML smuggling with setTimeout
1mo ago
Jan 12th, 2026
Sublime Security
Credential Phishing
Malware/Ransomware
Evasion
HTML smuggling
Scripting
Archive analysis
Content analysis
File analysis
HTML analysis
Javascript analysis
/feeds/core/detection-rules/attachment-html-smuggling-with-settimeout-4e0b2c32
Attachment: HTML smuggling 'body onload' with high entropy and suspicious text
1mo ago
Jan 12th, 2026
Sublime Security
Credential Phishing
Malware/Ransomware
Evasion
HTML smuggling
Scripting
Archive analysis
Content analysis
File analysis
HTML analysis
/feeds/core/detection-rules/attachment-html-smuggling-body-onload-with-high-entropy-and-suspicious-text-329ac12d
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