Detection Method: Optical Character Recognition

OCR (Optical Character Recognition) helps systems read and analyze text in images, screenshots, and scanned documents. This method turns visual text into machine-readable content, allowing your security tools to catch things that would normally slip past text-based filters.
OCR can help you detect:
  • Phishing text hidden in images to bypass text-based filters
  • Suspicious language or instructions in scanned documents
  • QR codes with malicious links
  • Brand impersonation attempts using image-based logos or text
  • Requests for sensitive information disguised in images
For example, attackers often embed fake login prompts or instructions to call a "customer support" number in images. These tricks are designed to bypass traditional security filters, but OCR can extract and analyze the text to flag it as malicious before it reaches you.
Blog Posts
Hiding a $50,000 BEC financial fraud in a fake email thread · Blog · Sublime Security
Hiding a $50,000 BEC financial fraud in a fake email thread · 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
Detecting Credential Phishing using Deep Learning + MQL · Blog · Sublime Security
Detecting Credential Phishing using Deep Learning + MQL · Blog · Sublime Security
Attack Types (6):
Callback Phishing
BEC/Fraud
Credential Phishing
Spam
Malware/Ransomware
Extortion
Tactics & Techniques (14):
Out of band pivot
Social engineering
PDF
Impersonation: Brand
Image as content
Free file host
Free subdomain host
Evasion
Free email provider
Macros
Open redirect
QR code
Spoofing
Encryption
Rule Name & Severity
Last Updated
Author
Types, Tactics & Capabilities
Callback phishing in body or attachment (untrusted sender)
1d ago
Jan 22nd, 2026
Sublime Security
Callback Phishing
Out of band pivot
Social engineering
Content analysis
File analysis
Optical Character Recognition
Natural Language Understanding
Sender analysis
/feeds/core/detection-rules/callback-phishing-in-body-or-attachment-untrusted-sender-b93c6f94
Attachment: Invoice and W-9 PDFs with suspicious creators
2d ago
Jan 21st, 2026
Sublime Security
BEC/Fraud
PDF
Social engineering
Impersonation: Brand
File analysis
Optical Character Recognition
Exif analysis
Content analysis
/feeds/core/detection-rules/attachment-invoice-and-w-9-pdfs-with-suspicious-creators-305d6e32
Brand impersonation: Fake Fax
2d ago
Jan 21st, 2026
Sublime Security
Credential Phishing
Impersonation: Brand
Image as content
Free file host
Free subdomain host
Social engineering
Computer Vision
Content analysis
Optical Character Recognition
Sender analysis
URL analysis
/feeds/core/detection-rules/brand-impersonation-fake-fax-2a96b90a
Brand impersonation: SendGrid
11d ago
Jan 12th, 2026
Sublime Security
BEC/Fraud
Credential Phishing
Spam
Impersonation: Brand
Social engineering
Content analysis
Header analysis
Natural Language Understanding
Optical Character Recognition
Sender analysis
/feeds/core/detection-rules/brand-impersonation-sendgrid-d800124f
Attachment: PDF with credential theft language and link to a free subdomain (unsolicited)
11d ago
Jan 12th, 2026
Sublime Security
Credential Phishing
Free subdomain host
PDF
Social engineering
File analysis
Natural Language Understanding
Optical Character Recognition
Sender analysis
URL analysis
/feeds/core/detection-rules/attachment-pdf-with-credential-theft-language-and-link-to-a-free-subdomain-unsolicited-90f4ef4e
Attachment: Office file with document sharing and browser instruction lures
11d ago
Jan 12th, 2026
Sublime Security
Credential Phishing
Social engineering
Evasion
Archive analysis
File analysis
Macro analysis
Optical Character Recognition
Content analysis
/feeds/core/detection-rules/attachment-office-file-with-document-sharing-and-browser-instruction-lures-b1250a4b
Callback phishing via Intuit service abuse
11d ago
Jan 12th, 2026
Sublime Security
Callback Phishing
Evasion
Free email provider
Impersonation: Brand
Social engineering
Computer Vision
Content analysis
Header analysis
Optical Character Recognition
/feeds/core/detection-rules/callback-phishing-via-intuit-service-abuse-f2fe1294
Brand impersonation: Internal Revenue Service
11d ago
Jan 12th, 2026
Sublime Security
BEC/Fraud
Credential Phishing
Impersonation: Brand
Social engineering
Content analysis
Natural Language Understanding
Optical Character Recognition
Sender analysis
/feeds/core/detection-rules/brand-impersonation-internal-revenue-service-3c63f8e9
Attachment: PDF with suspicious language and redirect to suspicious file type
11d ago
Jan 12th, 2026
Sublime Security
Malware/Ransomware
Credential Phishing
Evasion
PDF
File analysis
Natural Language Understanding
Optical Character Recognition
URL analysis
/feeds/core/detection-rules/attachment-pdf-with-suspicious-language-and-redirect-to-suspicious-file-type-adda3c3f
Attachment soliciting user to enable macros
11d ago
Jan 12th, 2026
Sublime Security
Malware/Ransomware
Macros
Archive analysis
File analysis
Macro analysis
Optical Character Recognition
Sender analysis
/feeds/core/detection-rules/attachment-soliciting-user-to-enable-macros-e9d75515
Callback phishing via e-signature service
11d ago
Jan 12th, 2026
Sublime Security
Callback Phishing
Free email provider
Impersonation: Brand
Social engineering
Content analysis
Computer Vision
Header analysis
Optical Character Recognition
/feeds/core/detection-rules/callback-phishing-via-e-signature-service-ed37b4fd
Callback phishing: Social Security Administration fraud
11d ago
Jan 12th, 2026
Sublime Security
Callback Phishing
Evasion
Free email provider
Out of band pivot
PDF
Social engineering
Exif analysis
File analysis
Optical Character Recognition
Sender analysis
/feeds/core/detection-rules/callback-phishing-social-security-administration-fraud-a9049d52
Callback phishing via extensionless rfc822 attachment
11d ago
Jan 12th, 2026
Sublime Security
Callback Phishing
Impersonation: Brand
Social engineering
File analysis
Natural Language Understanding
Optical Character Recognition
Sender analysis
/feeds/core/detection-rules/callback-phishing-via-extensionless-rfc822-attachment-197722c4
Fake scan-to-email message
11d ago
Jan 12th, 2026
Sublime Security
Credential Phishing
Free file host
Social engineering
Content analysis
Optical Character Recognition
Sender analysis
URL analysis
/feeds/core/detection-rules/fake-scan-to-email-message-78851fbe
Brand impersonation: Amazon with suspicious attachment
11d ago
Jan 12th, 2026
Sublime Security
Credential Phishing
Impersonation: Brand
Social engineering
Computer Vision
File analysis
Header analysis
Natural Language Understanding
Optical Character Recognition
Sender analysis
/feeds/core/detection-rules/brand-impersonation-amazon-with-suspicious-attachment-5751dcb9
Issuu document with suspicious embedded link
11d ago
Jan 12th, 2026
Sublime Security
Credential Phishing
Social engineering
Free file host
Evasion
URL analysis
URL screenshot
Natural Language Understanding
Optical Character Recognition
/feeds/core/detection-rules/issuu-document-with-suspicious-embedded-link-0d73f43d
Google Accelerated Mobile Pages (AMP) abuse
11d ago
Jan 12th, 2026
Sublime Security
Credential Phishing
Malware/Ransomware
Impersonation: Brand
Open redirect
Computer Vision
Content analysis
Natural Language Understanding
Optical Character Recognition
Sender analysis
URL analysis
URL screenshot
/feeds/core/detection-rules/google-accelerated-mobile-pages-amp-abuse-46907029
Brand impersonation: Google fake sign-in warning
11d ago
Jan 12th, 2026
Sublime Security
Credential Phishing
Impersonation: Brand
Social engineering
Computer Vision
File analysis
Optical Character Recognition
Sender analysis
URL analysis
/feeds/core/detection-rules/brand-impersonation-google-fake-sign-in-warning-2d998eee
Open Redirect: Google domain with /url path and suspicious indicators
11d ago
Jan 12th, 2026
Sublime Security
Credential Phishing
Evasion
Open redirect
Computer Vision
Content analysis
File analysis
Header analysis
Natural Language Understanding
Optical Character Recognition
Sender analysis
URL analysis
/feeds/core/detection-rules/open-redirect-google-domain-with-url-path-and-suspicious-indicators-fc5adf74
Link to auto-downloaded file with Google Drive branding
11d ago
Jan 12th, 2026
Sublime Security
Malware/Ransomware
Impersonation: Brand
Social engineering
Content analysis
File analysis
Optical Character Recognition
URL analysis
URL screenshot
/feeds/core/detection-rules/link-to-auto-downloaded-file-with-google-drive-branding-4b5343be
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