Medium Severity

Attachment: PDF Attachment with links to workers.dev

Labels

Credential Phishing
PDF
Free subdomain host
Evasion
File analysis
Exif analysis
URL analysis

Description

Detects inbound messages containing PDF attachments with fewer than 5 pages that, when analyzed, contain URLs pointing to workers.dev subdomains. This pattern indicates potential abuse of Cloudflare Workers infrastructure to host malicious content delivered via PDF documents.

References

No references.

Sublime Security
Created Jun 4th, 2026 • Last updated Jun 4th, 2026
Feed Source
Sublime Core Feed
Source
GitHub
type.inbound
and any(filter(attachments, .file_type == "pdf"),
        beta.parse_exif(.).page_count <= 2
        and any(file.explode(.),
                any(.scan.url.urls, .domain.root_domain == "workers.dev")
        )
)
MQL Rule Console
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