EXPLORE DETECTIONS
Attachment: RTF file with suspicious link
This rule detects RTF attachments directly attached or within an archive, containing an external link to a suspicious low reputation domain.
Attachment: RTF with embedded content
RTF files can contain embedded content similar to OLE files (Microsoft Office documents.)
Attachment: Self-sender PDF with minimal content and view prompt
Detects messages where the sender and recipient are the same address with a PDF attachment containing only 'VIEW PDF' text and a standardized body message requesting to view the attachment.
Attachment: SFX archive containing commands
Attachment is an SFX archive that contains commands that will execute when opened. This can be used to run malicious commands, and has been observed in the wild.
Attachment: Small text file with link containing recipient email address
Attach text file is less than 1000 bytes and contains a recipients email address. Seen in the wild carrying credential phishing links.
Attachment: Soda PDF producer with encryption themes
Detects an observed TTP of using Soda PDF (which offers a free trial) to produce PDFs which OCR output contains references to encryption and mentions a PDF. The PDF contains a single link which has been observed linking to a credential phishing page.
Attachment: Suspicious employee policy update document lure
Inbound message containing subject line and attachments related to handbook, compensation, or policy updates. Attachments are limited to Microsoft Word documents and match similar update-related terminology. This pattern has been observed used to delivery credential phishing via QR codes.
Attachment: Suspicious PDF created with headless browser
Detects PDF documents containing a table of contents that were generated using HeadlessChrome, Chromium with Skia/PDF, or QT with empty metadata fields - common characteristics of automated malicious document creation.
Attachment: Suspicious VBA macro
Detects any VBA macro attachment that scores above a low confidence threshold in the Sublime Macro Classifier.
Attachment: SVG file execution
Detects file execution attempts in SVG files. ActiveXObject is used to invoke WScript.Shell and run a program.
Attachment: SVG files with evasion elements
This rule identifies incoming SVG vector graphics files containing specific patterns: circle elements combined with either embedded images, QR codes, or filenames that match recipient information. Limited to three attachments and validates sender authenticity. SVG circle elements have been used to obfuscate QR codes and bypass automated QR code scanning methods.
Attachment: Uncommon compressed file
Use if passing compressed or archive files is not typical behavior in your organization. This behavior has been observed in a number of phishing campaigns.
Attachment: USDA bid invitation impersonation
Detects messages claiming to be from USDA containing bid invitations with macro-enabled attachments or PDFs. Validates USDA-related content through OCR and natural language analysis.
Attachment: Web files with suspicious comments
Detects HTML or SVG files under 100KB that contain duplicate or padding text in the form of literary quotes or common sayings within code comments.
Attachment: WinRAR CVE-2025-8088 exploitation
Detects attempts to exploit CVE-2025-8088 via attached RAR files
Attachment: XLSX file with suspicious print titles metadata
Detects XLSX attachments containing EXIF metadata with suspicious TitlesOfParts fields that follow a specific pattern combining 'Company_Name' with extracted values and 'Print_Titles', potentially indicating malicious document preparation.
Attachment: Zip exploiting CVE-2023-38831 (unsolicited)
A Zip attachment that exhibits attributes required to exploit CVE-2023-38831, a vulnerability in WinRAR (prior to 6.23).
Attachment: ZIP file with CVE-2026-0866 exploit
Detects ZIP attachments containing exploits targeting CVE-2026-0866 vulnerability through YARA signature matching.
BEC with unusual reply-to or return-path mismatch
Detects an unusual header mismatch where the sender is not a freemail address, but the reply-to or return-path are. NLU also detects a BEC intent with medium or high confidence.
BEC: Employee impersonation with subject manipulation
Subject matches the display name of someone in your organization, and the body resembles a BEC attack.
BEC/Fraud: Generic scam attempt to undisclosed recipients
Detects potential generic scams by analyzing text within the email body and other suspicious signals.
BEC/Fraud: Job scam fake thread or plaintext pivot to freemail
Detects potential job scams using plaintext or fake threads attempting to pivot to a freemail address from an unsolicited sender.
BEC/Fraud: Penpal scam
This rule detects messages from individuals looking to establish contact under the guise of seeking friendship or a penpal relationship. Over time, they build trust and then exploit this relationship by asking for money, personal information, or involvement in suspicious activities.
BEC/Fraud: Reply-chain manipulation with urgent keywords and self-reply
Detects suspicious reply messages with urgent language in sender name or email address, minimal body content, and the sender's email address appearing in previous thread content, indicating a self reply.