Malicious PDF — malware analysis report

Static analysis result for SHA-256 21a10c0dfab33032…

MALICIOUS

PDF

79.9 KB Created: 2021-09-15 13:19:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: 4aafa99ded9ad97b863b7db684b74557 SHA-1: 8b01a65db69b78427b299e5763c09794b7dc2f42 SHA-256: 21a10c0dfab330328104dbe5adad5584a36578129cfe165882f4390bcc88c288
156 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, with heuristics indicating it functions as a link farm. Several embedded URLs point to compromised CMS uploads and disposable hosting, suggesting an attempt to redirect users to malicious content. The presence of PDF_URI and PDF_SEO_DISPOSABLE_LINK_FARM heuristics strongly supports a phishing or malware distribution attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9966

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://classconnbio.com/img-jacson/files/69937949159.pdf In PDF document text
    • http://msdoubrava.cz/foto/images/file/57444791176.pdfIn PDF document text
    • http://obras.ru/sites/default/files/uploads/51256413423.pdfIn PDF document text
    • http://elosc.com/upFile/file///ITX202109070205218620.pdfIn PDF document text
    • http://driscollandgibson.com/images/edit_images/file/kojosukofuluxavikumevo.pdfIn PDF document text
    • http://gardatrans.com/content/Files/xibofibeputumisosir.pdfIn PDF document text
    • http://soepcentrale-dekeyser.be/userfiles/file/wafinikatazikis.pdfIn PDF document text
    • http://dinskayarealty.ru/media/file/20678468240.pdfIn PDF document text
    • http://thaide.org/userfiles/file/23889873210.pdfIn PDF document text
    • http://xn--b1agjlwjc3g.xn--p1ai/ckfinder/userfiles/files/66386501033.pdfIn PDF document text
    • https://2-view.org/home/view/public_html/ckfinder/userfiles/files/96735358930.pdfIn PDF document text
    • https://mertlakustika.cz/images/pages/file/bamugotopogugolix.pdfIn PDF document text
    • http://ayurveda-shiatsu-qigong-nice.com/upload/files/66688640594.pdfIn PDF document text
    • https://delphin-restaurant.com/ckfinder/upload/files/73872698673.pdfIn PDF document text
    • https://rachelrom.com/rescontent/file/wofogutolepigiposofarilod.pdfIn PDF document text
    • https://holzhaus-suedtirol.it/wp-content/plugins/formcraft/file-upload/server/content/files/1613df0c32dbae---21025181843.pdfIn PDF document text
    • http://logicamail.it/draft/media/73083542210.pdfIn PDF document text
    • http://xn--80ackbssfuieecff0e8c.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/2b9kus2ifd2e8aeaqn25cs7i72/tavesasepalanevekabefobag.pdfIn PDF document text
    • http://cohn-vossen.com/wp-content/plugins/formcraft/file-upload/server/content/files/16140c143c2159---wokefibupozatalenazubexiw.pdfIn PDF document text
    • http://denis-lefebvre-services.com/fichiers/file/17805970788.pdfIn PDF document text
    • http://autoscuolecasetta.it/userfiles/files/wajozogud.pdfIn PDF document text
    • http://www.guaitoli.eng.br/wp-content/plugins/formcraft/file-upload/server/content/files/161348cd3ecf20---kogelumasiken.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=reface+mod+apk+without+watermarkPDF 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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000beeb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBEEB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d6f8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD6F8 1868 bytes
SHA-256: b44e304f4199d162c520aa61e4565b27969aa952fa2ee1db3f4cf671ae1a9eb8
font_02_sfnt_off0000dfb0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDFB0 10892 bytes
SHA-256: 8fe36473c7ee1e48968ab8e724957847543a86c873931c37cdfb37471c6e67e6
font_03_sfnt_off0000f8f5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF8F5 22436 bytes
SHA-256: dfb8055990d36576f4f73f0a64fffa70a83936e8bfcb425d3a1b097f92807ef2

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