Tactic or Technique: PDF

Attackers use PDF files to deliver malicious content in a format that most people see as safe. These files often appear to be invoices, contracts, or notifications and can include embedded JavaScript, links, or QR codes that lead to phishing sites or malware downloads.
One common example is a fake DocuSign PDF that asks you to scan a QR code or click a link to view a document. The moment you interact, you're taken to a phishing site designed to steal your credentials or deliver malware.
Because PDFs are trusted and can difficult to inspect, they give attackers a way to hide dangerous content behind a familiar format. That trust, combined with limited scanning by some security tools, gives malicious PDFs a clear path into inboxes and environments.
Blog Posts
Tax season email attacks: AdWind RATs and Tycoon 2FA phishing kits · Blog · Sublime Security
Tax season email attacks: AdWind RATs and Tycoon 2FA phishing kits · Blog · Sublime Security
Callback phishing via invoice abuse and distribution list relays · Blog · Sublime Security
Callback phishing via invoice abuse and distribution list relays · Blog · Sublime Security
Talking phish over turkey · Blog · Sublime Security
Talking phish over turkey · Blog · Sublime Security
Abusing Discord to deliver Agent Tesla malware · Blog · Sublime Security
Abusing Discord to deliver Agent Tesla malware · Blog · Sublime Security
Fake invoice used to conduct $16,800 BEC attempt · Blog · Sublime Security
Fake invoice used to conduct $16,800 BEC attempt · Blog · Sublime Security
Gotta Catch 'Em All: Detecting PikaBot Delivery Techniques · Blog · Sublime Security
Gotta Catch 'Em All: Detecting PikaBot Delivery Techniques · 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 QakBot: WSF attachments, OneNote files, and generic attack surface reduction · Blog · Sublime Security
Detecting QakBot: WSF attachments, OneNote files, and generic attack surface reduction · Blog · Sublime Security
Attack Types (6):
Credential Phishing
BEC/Fraud
Callback Phishing
Malware/Ransomware
Extortion
Spam
Detection Methods (14):
Content analysis
File analysis
Sender analysis
Exif analysis
Optical Character Recognition
QR code analysis
Natural Language Understanding
Header analysis
Archive analysis
URL analysis
Whois
Computer Vision
HTML analysis
Threat intelligence
Rule Name & Severity
Last Updated
Author
Types, Tactics & Capabilities
Attachment: Suspicious employee policy update document lure
7d ago
Dec 26th, 2025
Sublime Security
Credential Phishing
PDF
Social engineering
Evasion
Content analysis
File analysis
Sender analysis
/feeds/core/detection-rules/attachment-suspicious-employee-policy-update-document-lure-a8bf1fd1
Attachment: PDF generated with wkhtmltopdf tool and default title
14d ago
Dec 19th, 2025
Sublime Security
BEC/Fraud
Callback Phishing
Credential Phishing
Malware/Ransomware
PDF
Evasion
File analysis
Exif analysis
/feeds/core/detection-rules/attachment-pdf-generated-with-wkhtmltopdf-tool-and-default-title-64e6c8a8
Attachment: Compensation review lure with QR code
23d ago
Dec 10th, 2025
Sublime Security
Credential Phishing
PDF
QR code
Social engineering
File analysis
Optical Character Recognition
QR code analysis
Natural Language Understanding
Sender analysis
Header analysis
/feeds/core/detection-rules/attachment-compensation-review-lure-with-qr-code-9fd8185c
Attachment: PDF with link to DMG file download
23d ago
Dec 10th, 2025
Sublime Security
Malware/Ransomware
Evasion
PDF
Archive analysis
Content analysis
File analysis
URL analysis
/feeds/core/detection-rules/attachment-pdf-with-link-to-dmg-file-download-2c486fe0
Attachment: PDF with personal Microsoft OneNote URL
29d ago
Dec 4th, 2025
Sublime Security
Credential Phishing
PDF
Social engineering
File analysis
Content analysis
/feeds/core/detection-rules/attachment-pdf-with-personal-microsoft-onenote-url-0675bbc5
Attachment: Encrypted PDF with credential theft body
1mo ago
Dec 1st, 2025
Sublime Security
Credential Phishing
Encryption
Evasion
PDF
Social engineering
Content analysis
Exif analysis
File analysis
Natural Language Understanding
Sender analysis
/feeds/core/detection-rules/attachment-encrypted-pdf-with-credential-theft-body-c9596c9a
Attachment: Legal themed message or PDF with suspicious indicators
1mo ago
Dec 1st, 2025
Sublime Security
Credential Phishing
Extortion
BEC/Fraud
Evasion
PDF
Social engineering
Content analysis
File analysis
Natural Language Understanding
Optical Character Recognition
URL analysis
Whois
Header analysis
Exif analysis
/feeds/core/detection-rules/attachment-legal-themed-message-or-pdf-with-suspicious-indicators-19133301
Attachment: PDF with Microsoft Purview message impersonation
1mo ago
Nov 10th, 2025
Sublime Security
Credential Phishing
Impersonation: Brand
PDF
Social engineering
File analysis
Natural Language Understanding
Content analysis
/feeds/core/detection-rules/attachment-pdf-with-microsoft-purview-message-impersonation-571d4964
Brand impersonation: SharePoint PDF attachment with credential theft language
1mo ago
Nov 7th, 2025
Sublime Security
Credential Phishing
Impersonation: Brand
Social engineering
PDF
Evasion
Computer Vision
File analysis
Natural Language Understanding
Optical Character Recognition
Sender analysis
URL analysis
Header analysis
Whois
/feeds/core/detection-rules/brand-impersonation-sharepoint-pdf-attachment-with-credential-theft-language-ae3756fa
Brand impersonation: DocuSign PDF attachment with suspicious link
2mo ago
Oct 22nd, 2025
Sublime Security
Credential Phishing
Impersonation: Brand
PDF
Social engineering
File analysis
Natural Language Understanding
Optical Character Recognition
URL analysis
/feeds/core/detection-rules/brand-impersonation-docusign-pdf-attachment-with-suspicious-link-2601cbb7
Brand Impersonation: Google (QR Code)
2mo ago
Oct 17th, 2025
Sublime Security
Credential Phishing
Impersonation: Brand
PDF
QR code
Computer Vision
Header analysis
QR code analysis
Sender analysis
/feeds/core/detection-rules/brand-impersonation-google-qr-code-7ffd184c
Brand impersonation: DocuSign (QR code)
2mo ago
Oct 15th, 2025
Sublime Security
Credential Phishing
Impersonation: Brand
PDF
QR code
Social engineering
Computer Vision
Header analysis
QR code analysis
Sender analysis
/feeds/core/detection-rules/brand-impersonation-docusign-qr-code-0b16c28a
Attachment: PDF with recipient email in link
2mo ago
Oct 10th, 2025
Sublime Security
Credential Phishing
PDF
QR code
Encryption
Social engineering
File analysis
QR code analysis
URL analysis
/feeds/core/detection-rules/attachment-pdf-with-recipient-email-in-link-0399d08f
Brand impersonation: Adobe (QR code)
3mo ago
Oct 3rd, 2025
Sublime Security
Credential Phishing
Impersonation: Brand
PDF
QR code
Computer Vision
Header analysis
QR code analysis
Sender analysis
/feeds/core/detection-rules/brand-impersonation-adobe-qr-code-2fc36c6d
Brand impersonation: Microsoft (QR code)
3mo ago
Sep 22nd, 2025
Sublime Security
Credential Phishing
Impersonation: Brand
PDF
QR code
Social engineering
Computer Vision
Header analysis
QR code analysis
Sender analysis
/feeds/core/detection-rules/brand-impersonation-microsoft-qr-code-ed0f772a
Attachment: Fake scan-to-email
3mo ago
Sep 22nd, 2025
Sublime Security
Credential Phishing
Free file host
Image as content
PDF
Social engineering
Content analysis
File analysis
Natural Language Understanding
Optical Character Recognition
Sender analysis
/feeds/core/detection-rules/attachment-fake-scan-to-email-ea850cc1
Sharepoint link likely unrelated to sender
3mo ago
Sep 19th, 2025
Sublime Security
BEC/Fraud
Credential Phishing
Impersonation: Employee
Lookalike domain
OneNote
PDF
Social engineering
URL analysis
Sender analysis
Header analysis
HTML analysis
/feeds/core/detection-rules/sharepoint-link-likely-unrelated-to-sender-6870f489
Attachment: Suspicious PDF created with headless browser
3mo ago
Sep 17th, 2025
Sublime Security
Credential Phishing
Evasion
PDF
Content analysis
Exif analysis
File analysis
Optical Character Recognition
/feeds/core/detection-rules/attachment-suspicious-pdf-created-with-headless-browser-8f3108d7
Credential phishing: Tax form impersonation with payment request
3mo ago
Sep 10th, 2025
Sublime Security
BEC/Fraud
Credential Phishing
Impersonation: Brand
Social engineering
PDF
Content analysis
Header analysis
Sender analysis
URL analysis
/feeds/core/detection-rules/credential-phishing-tax-form-impersonation-with-payment-request-717695cf
Attachment: Fictitious invoice using LinkedIn's address
4mo ago
Sep 3rd, 2025
Sublime Security
BEC/Fraud
PDF
Social engineering
File analysis
Optical Character Recognition
Natural Language Understanding
Content analysis
Exif analysis
/feeds/core/detection-rules/attachment-fictitious-invoice-using-linkedins-address-aeee3d9f
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