Malicious PDF — malware analysis report

Static analysis result for SHA-256 db4333f87630642a…

MALICIOUS

PDF

62.5 KB Created: 2021-09-08 06:31:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: d565dbf6b6b0d0d430b0e16aeebd9fa3 SHA-1: bdbe1d98d4ea7dfcc5cb508513ce14a8950a0614 SHA-256: db4333f87630642af14a4adfd3895e04e04882495917c7a5072f7729c463a0bd
64 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains multiple embedded URLs that point to other PDF files hosted on various domains. Several heuristics indicate these are part of a link farm, with some links pointing to compromised WordPress upload directories. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user interaction but rather as a vehicle for distributing links.

Machine Learning

  • Nyx PDF Classifier suspicious score 0.3712

Heuristics 4

  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://stellarp.com/userfiles/files/63775947184.pdf In PDF document text
    • http://www.iqubz.com/wp-content/plugins/formcraft/file-upload/server/content/files/160944eb75e9df---vajegudorivoxiruw.pdfIn PDF document text
    • http://bandenplaats.nl/cmsimages/file/wiponerutawar.pdfIn PDF document text
    • https://acryl-bg.com/userfiles/file/77719542909.pdfIn PDF document text
    • http://szyqjsj.com/UploadFile/file/20210827013012453.pdfIn PDF document text
    • https://barcelonamedicalcenter.com/files/galeria/files/25719479254.pdfIn PDF document text
    • http://www.rkcomdesignservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609c305c19dde---17398946745.pdfIn PDF document text
    • https://inchiriereelicoptere.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160fff91e0b9ae---jerisikinesikov.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/fzgW7-mxBc0/uplcv?utm_term=basic+english+parts+of+speech+pdfPDF link annotation

Related samples 8

Ranked by shared artifacts, heuristics, extracted URLs, CVEs, and signatures.

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