Malicious PDF — malware analysis report

Static analysis result for SHA-256 d3bf18e31def9c87…

MALICIOUS

PDF

82.3 KB Created: 2021-06-13 08:32:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-24
MD5: a16a7853084f6f255e39c00af2776b94 SHA-1: ab697c9d40ee63eed87baa21dcf47a77904e2c5c SHA-256: d3bf18e31def9c8760b84964afe2d234ba2ec6268da58be0f15a8ea1f546d75a
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

This PDF file was detected as malicious by ClamAV and an ML classifier. It functions as a link farm, containing numerous URLs pointing to various websites, some of which are hosted on compromised WordPress installations. The document body, though heavily obfuscated, suggests a lure related to 'critical reasoning test questions and answers', likely a pretext for phishing or directing users to malicious content. No scripts were extracted, but the presence of multiple external links on potentially compromised infrastructure indicates a high likelihood of malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 https://pistant.ru/uplcv?utm_term=critical+reasoning+test+questions+and+answers PDF link annotation
    • http://barcelonasixtytwo.com/userfiles/file/zubig.pdfIn PDF document text
    • https://glowskincare.net/wp-content/plugins/super-forms/uploads/php/files/f68b24e3671847bb724ab78bcf744ac6/dijejidowusixipap.pdfIn PDF document text
    • http://www.blackhillsdancecentre.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b7dc3fb76d1---jaxamopidekevegote.pdfIn PDF document text
    • http://edwardlankin.com/clients/86087/File/lefemugifas.pdfIn PDF document text
    • https://rclurie.com/wp-content/plugins/super-forms/uploads/php/files/01c37a7557c5d5bb1c56fbe2dab4f003/nidazikag.pdfIn PDF document text
    • http://extintoresorigen.com/images/editor/57602048067.pdfIn PDF document text
    • https://maloneslandscape.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606c9d84353b0---54554375420.pdfIn PDF document text
    • https://proff-doors.ru/wp-content/plugins/super-forms/uploads/php/files/29890029df4fcbb1996a631a032894f4/40369102358.pdfIn PDF document text
    • https://maloneslandscape.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607c319a8d390---fabagabalirumex.pdfIn PDF document text
    • https://deewo.de/wp-content/plugins/formcraft/file-upload/server/content/files/16083b11382173---2678345575.pdfIn PDF document text
    • https://nuevocoach.co.uk/wp-content/plugins/super-forms/uploads/php/files/5dd33a021c1c59997a918d95163a0b23/rakujopadozegarewemo.pdfIn PDF document text
    • http://www.auditsi.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f487999d2e---wofodotazoximexadoz.pdfIn PDF document text
    • https://nationalcardsolutions.com/wp-content/plugins/formcraft/file-upload/server/content/files/160985eb614bd3---zupisivenopekero.pdfIn PDF document text
    • http://gsoam.ge/wp-content/plugins/formcraft/file-upload/server/content/files/1607b5b7aebdae---88385172426.pdfIn PDF document text
    • http://www.optionassurance.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160839701317d7---befowobulebodijiji.pdfIn PDF document text
    • https://gmonlinestore.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608404cba34fd---kavemasodozometar.pdfIn PDF document text
    • https://broadstripe.com/wp-content/plugins/super-forms/uploads/php/files/d5650c8faad6186dd282ce1690180344/51773385025.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • 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_off00010470.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10470 5232 bytes
SHA-256: f49615359a323e7710e01cefc973b739e38335c5a0434e08d97fdac7dd3b1ac8
font_01_sfnt_off00011646.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11646 11124 bytes
SHA-256: 0f473d64c2c2eeb9f957409c08b504be4e543381b2153c29a54341a05222f653

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