Sublime Security

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HTML analysis
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Attack Types
BEC/Fraud
Callback Phishing
Credential Phishing
Extortion
Malware/Ransomware
Reconnaissance
Spam
Tactics and Techniques
Encryption
Evasion
Exploit
Free email provider
Free file host
Free subdomain host
HTML smuggling
Image as content
Impersonation: Brand
Impersonation: Employee
Impersonation: VIP
IPFS
ISO
LNK
Lookalike domain
Macros
OneNote
Open redirect
Out of band pivot
PDF
Punycode
QR code
Scripting
Social engineering
Spoofing
Detection Methods
Archive analysis
Content analysis
Computer Vision
Exif analysis
File analysis
Header analysis
HTML analysis
Javascript analysis
Macro analysis
Natural Language Understanding
Optical Character Recognition
OLE analysis
PDF analysis
QR code analysis
Sender analysis
Threat intelligence
URL analysis
URL screenshot
Whois
XML analysis
YARA
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
Living Off the Land: Credential Phishing via Docusign abuse · Blog · Sublime Security
Call Me Maybe? The Rise of Callback Phishing Emails · Blog · Sublime Security
Attack Types (6):
Credential Phishing
Spam
BEC/Fraud
Malware/Ransomware
Callback Phishing
Extortion
Tactics & Techniques (21):
Impersonation: Brand
Social engineering
Evasion
Impersonation: VIP
Lookalike domain
Free subdomain host
Credential Phishing
HTML smuggling
Scripting
Encryption
Exploit
Free file host
Open redirect
Free email provider
Image as content
HTML injection
Impersonation: Employee
OneNote
PDF
Out of band pivot
ISO
Rule Name & Severity
Last Updated
Types, Tactics & Capabilities
Brand impersonation: Microsoft Teams invitation
6d ago
Feb 6th, 2026
Sublime Security
Credential Phishing
Impersonation: Brand
Social engineering
Content analysis
Header analysis
HTML analysis
URL analysis
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
6d ago
Feb 6th, 2026
Sublime Security
Spam
Social engineering
Content analysis
HTML analysis
Natural Language Understanding
Sender analysis
URL analysis
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
9d ago
Feb 3rd, 2026
Sublime Security
Credential Phishing
Evasion
URL analysis
HTML analysis
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
9d ago
Feb 3rd, 2026
Sublime Security
Credential Phishing
Impersonation: VIP
Social engineering
Content analysis
Header analysis
HTML analysis
Sender analysis
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
15d 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
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
20d ago
Jan 23rd, 2026
Sublime Security
Credential Phishing
Impersonation: Brand
Social engineering
Evasion
HTML analysis
Computer Vision
Content analysis
Header analysis
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)
20d ago
Jan 23rd, 2026
Sublime Security
Credential Phishing
Free subdomain host
Evasion
Credential Phishing
URL analysis
HTML analysis
Content analysis
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
29d ago
Jan 14th, 2026
Sublime Security
Spam
Impersonation: Brand
Social engineering
Content analysis
HTML analysis
Sender analysis
URL analysis
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
Request for Quote or Purchase (RFQ|RFP) with HTML smuggling attachment
1mo ago
Jan 12th, 2026
Sublime Security
Credential Phishing
Evasion
Content analysis
File analysis
HTML analysis
Javascript analysis
Natural Language Understanding
URL analysis
Credential Phishing
Evasion
Content analysis
File analysis
HTML analysis
Javascript analysis
Natural Language Understanding
URL analysis
/feeds/core/detection-rules/request-for-quote-or-purchase-rfqorrfp-with-html-smuggling-attachment-a47a5755
Attachment: HTML smuggling with eval and atob via calendar invite
1mo ago
Jan 12th, 2026
Sublime Security
Credential Phishing
Malware/Ransomware
Evasion
HTML smuggling
Scripting
File analysis
HTML analysis
Javascript analysis
Credential Phishing
Malware/Ransomware
Evasion
HTML smuggling
Scripting
File analysis
HTML analysis
Javascript analysis
/feeds/core/detection-rules/attachment-html-smuggling-with-eval-and-atob-via-calendar-invite-597c2edd
Service abuse: Random Google Firebase sender address with suspicious content
1mo ago
Jan 12th, 2026
Sublime Security
Spam
Credential Phishing
Free subdomain host
Social engineering
Content analysis
Header analysis
HTML analysis
Natural Language Understanding
Sender analysis
URL analysis
Whois
Spam
Credential Phishing
Free subdomain host
Social engineering
Content analysis
Header analysis
HTML analysis
Natural Language Understanding
Sender analysis
URL analysis
Whois
/feeds/core/detection-rules/service-abuse-random-google-firebase-sender-address-with-suspicious-content-9f8899a9
Attachment: HTML smuggling with ROT13
1mo ago
Jan 12th, 2026
@Kyle_Parrish_
Credential Phishing
Malware/Ransomware
Encryption
Evasion
HTML smuggling
Scripting
Archive analysis
Content analysis
File analysis
Javascript analysis
HTML analysis
Credential Phishing
Malware/Ransomware
Encryption
Evasion
HTML smuggling
Scripting
Archive analysis
Content analysis
File analysis
Javascript analysis
HTML analysis
/feeds/core/detection-rules/attachment-html-smuggling-with-rot13-6eacc4cf
CVE-2023-5631 - Roundcube Webmail XSS via crafted SVG
1mo ago
Jan 12th, 2026
Sublime Security
Malware/Ransomware
Evasion
Exploit
HTML smuggling
Scripting
Content analysis
HTML analysis
Sender analysis
Malware/Ransomware
Evasion
Exploit
HTML smuggling
Scripting
Content analysis
HTML analysis
Sender analysis
/feeds/core/detection-rules/cve-2023-5631-roundcube-webmail-xss-via-crafted-svg-8405d61b
Low reputation link to auto-downloaded HTML file with smuggling indicators
1mo ago
Jan 12th, 2026
Sublime Security
Credential Phishing
Evasion
Free file host
Free subdomain host
HTML smuggling
Impersonation: Brand
Open redirect
Social engineering
Content analysis
File analysis
HTML analysis
Javascript analysis
Sender analysis
URL analysis
Credential Phishing
Evasion
Free file host
Free subdomain host
HTML smuggling
Impersonation: Brand
Open redirect
Social engineering
Content analysis
File analysis
HTML analysis
Javascript analysis
Sender analysis
URL analysis
/feeds/core/detection-rules/low-reputation-link-to-auto-downloaded-html-file-with-smuggling-indicators-339676c6
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
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
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
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
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
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
Attachment: HTML smuggling with unescape
1mo ago
Jan 12th, 2026
Sublime Security
Credential Phishing
Malware/Ransomware
Evasion
HTML smuggling
Scripting
Archive analysis
File analysis
HTML analysis
Javascript analysis
Credential Phishing
Malware/Ransomware
Evasion
HTML smuggling
Scripting
Archive analysis
File analysis
HTML analysis
Javascript analysis
/feeds/core/detection-rules/attachment-html-smuggling-with-unescape-0b0fed36
Page 1 of 5

Rule Name & Severity	Last Updated	Author	Types, Tactics & Capabilities
Brand impersonation: Microsoft Teams invitation	6d 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	6d 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	9d 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	9d 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	15d 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	20d 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)	20d 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	29d 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
Request for Quote or Purchase (RFQ\|RFP) with HTML smuggling attachment	1mo ago Jan 12th, 2026	Sublime Security	Credential Phishing Evasion Content analysis File analysis HTML analysis Javascript analysis Natural Language Understanding URL analysis	/feeds/core/detection-rules/request-for-quote-or-purchase-rfqorrfp-with-html-smuggling-attachment-a47a5755
Attachment: HTML smuggling with eval and atob via calendar invite	1mo ago Jan 12th, 2026	Sublime Security	Credential Phishing Malware/Ransomware Evasion HTML smuggling Scripting File analysis HTML analysis Javascript analysis	/feeds/core/detection-rules/attachment-html-smuggling-with-eval-and-atob-via-calendar-invite-597c2edd
Service abuse: Random Google Firebase sender address with suspicious content	1mo ago Jan 12th, 2026	Sublime Security	Spam Credential Phishing Free subdomain host Social engineering Content analysis Header analysis HTML analysis Natural Language Understanding Sender analysis URL analysis Whois	/feeds/core/detection-rules/service-abuse-random-google-firebase-sender-address-with-suspicious-content-9f8899a9
Attachment: HTML smuggling with ROT13	1mo ago Jan 12th, 2026	@Kyle_Parrish_	Credential Phishing Malware/Ransomware Encryption Evasion HTML smuggling Scripting Archive analysis Content analysis File analysis Javascript analysis HTML analysis	/feeds/core/detection-rules/attachment-html-smuggling-with-rot13-6eacc4cf
CVE-2023-5631 - Roundcube Webmail XSS via crafted SVG	1mo ago Jan 12th, 2026	Sublime Security	Malware/Ransomware Evasion Exploit HTML smuggling Scripting Content analysis HTML analysis Sender analysis	/feeds/core/detection-rules/cve-2023-5631-roundcube-webmail-xss-via-crafted-svg-8405d61b
Low reputation link to auto-downloaded HTML file with smuggling indicators	1mo ago Jan 12th, 2026	Sublime Security	Credential Phishing Evasion Free file host Free subdomain host HTML smuggling Impersonation: Brand Open redirect Social engineering Content analysis File analysis HTML analysis Javascript analysis Sender analysis URL analysis	/feeds/core/detection-rules/low-reputation-link-to-auto-downloaded-html-file-with-smuggling-indicators-339676c6
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
Attachment: HTML smuggling with unescape	1mo ago Jan 12th, 2026	Sublime Security	Credential Phishing Malware/Ransomware Evasion HTML smuggling Scripting Archive analysis File analysis HTML analysis Javascript analysis	/feeds/core/detection-rules/attachment-html-smuggling-with-unescape-0b0fed36