Malicious PDF — malware analysis report

Static analysis result for SHA-256 ec77400dd36afc88…

MALICIOUS

PDF

159.4 KB Created: 2021-05-17 16:07:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-14
MD5: 53ae0c1bf14771d5caac4663008b9ea7 SHA-1: 6c91ed9cf1ebd7a889510f880c19cabecaa4fd7d SHA-256: ec77400dd36afc88f0858a2ac2f222ede875657c666738f78bc6466c58eebb3d
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF was flagged by ClamAV as Pdf.Phishing.Trojan and an ML classifier indicated high maliciousness. Heuristics identified it as a link farm pointing to compromised WordPress upload storage, suggesting it's designed to lure users to malicious content. The document body is heavily obfuscated and contains metadata indicating it was generated by wkhtmltopdf.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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://www.timtransportes.com/home/wp-content/plugins/formcraft/file-upload/server/content/files/16072355c8296c---84266634767.pdf In PDF document text
    • http://belgium-ex.com/images/blog//file/5112090827.pdfIn PDF document text
    • https://southtours.com/wp-content/plugins/super-forms/uploads/php/files/cko47qsl0up5hk4n9to1t6tngr/26418540714.pdfIn PDF document text
    • http://asdgolfclubtoscana.com/writable/public/userfiles/file/94276689216.pdfIn PDF document text
    • https://spencershaulageltd.co.uk/wp-content/plugins/super-forms/uploads/php/files/51441490867fb7626d6137fed6af8bf9/nigizijurarumur.pdfIn PDF document text
    • https://retentionstudentexperience.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607068f76a7bd---runitudefar.pdfIn PDF document text
    • http://asalsold.com/wp-content/plugins/formcraft/file-upload/server/content/files/16084eda8ef510---84801771805.pdfIn PDF document text
    • http://zonazero.es/userfiles/file/biwusepezumonag.pdfIn PDF document text
    • http://halvani.com/wp-content/plugins/formcraft/file-upload/server/content/files/16087fd4baf38d---57858005485.pdfIn PDF document text
    • https://homini.eu/wp-content/plugins/formcraft/file-upload/server/content/files/1606cc7f97e109---fokevuxudipimun.pdfIn PDF document text
    • https://agribusiness.pk/wp-content/plugins/formcraft/file-upload/server/content/files/1606d1dbbf0c50---segemuzatun.pdfIn PDF document text
    • http://apexibd.com/uploads/fck_uploads/file/javimagabukozoveza.pdfIn PDF document text
    • https://damiel.eu/userfiles/file/ximepenam.pdfIn PDF document text
    • http://premiumresourcing.com/wp-content/plugins/formcraft/file-upload/server/content/files/160968bfc30281---xemuj.pdfIn PDF document text
    • https://heatingboiler.ca/fck_upload/file/munerira.pdfIn PDF document text
    • https://aronabritcan.com/userfiles/file/57911515758.pdfIn PDF document text
    • https://www.demetagras.com/wp-content/plugins/formcraft/file-upload/server/content/files/160788ad42f2c9---33938976797.pdfIn PDF document text
    • https://www.hontoys.com.au/wp-content/plugins/super-forms/uploads/php/files/v67fqsai9a95baa67mshaq876e/vuxeridumerojezifes.pdfIn PDF document text
    • http://www.recetasyconsejos.com/wp-content/plugins/formcraft/file-upload/server/content/files/160969c3732734---pisovogemofetakut.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/3vuEKuznOb8/uplcv?utm_term=baumannii+bacteria+pdfPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000232da.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x232DA 5280 bytes
SHA-256: 0e007f0b1d81fa37fd6471491e74cd7e7b40ec045f205bb3e3614a0a6e48679b
font_01_sfnt_off000244b2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x244B2 13100 bytes
SHA-256: 47136768600208b7f9b23f25c3ffb72b27baf5532463733bc1fba2e513ac98be