Malicious PDF — malware analysis report

Static analysis result for SHA-256 5b1a3e8cdbc88459…

MALICIOUS

PDF

83.8 KB Created: 2021-09-02 14:00:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 53c81884ac34eea3f2bbf8e37708896e SHA-1: 6f4a4bd8abbd522e4d20e584c2d7feb72b80c11e SHA-256: 5b1a3e8cdbc88459ccf88adb9015adefbb5581f9b99c18c738b07ebf07db29a4
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was flagged by multiple heuristics as malicious, including a critical ClamAV detection and an ML classifier. It contains a large number of links, many pointing to compromised CMS upload directories or disposable hosting, suggesting a link farm designed for SEO manipulation or to host malicious content. While no scripts were explicitly extracted, the PDF structure and link farm behavior are indicative of a phishing or malware distribution attempt, likely delivered via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9860

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://limblength-sldf.com/userfiles/file/fatodexizinigesufopuwo.pdf In PDF document text
    • http://hrudolf.com/userfiles/15041092055.pdfIn PDF document text
    • https://www.natursany.com//ckfinder/userfiles/files/71747499613.pdfIn PDF document text
    • http://actionelectric.pt/www/wp-content/plugins/formcraft/file-upload/server/content/files/1607c56643f757---52993979557.pdfIn PDF document text
    • https://cristiandellavedova.com/wp-content/plugins/super-forms/uploads/php/files/9h0grn32t902v5tnmnn25qh1h7/gegezuzex.pdfIn PDF document text
    • https://carpanea.it/wp-content/plugins/super-forms/uploads/php/files/90f6dd3a51668398332eab927fc2a573/wofipisitos.pdfIn PDF document text
    • http://gianniarnaudo.com/userfiles/files/40679493992.pdfIn PDF document text
    • https://ecobox.eng.br/wp-content/plugins/super-forms/uploads/php/files/hs12iviipa3m0jcmij4m0lshpc/60136693236.pdfIn PDF document text
    • http://osmed.cz/app/webroot/files/files/83298508223.pdfIn PDF document text
    • https://www.infratechgroep.nl/wp-content/plugins/super-forms/uploads/php/files/d5fb605496a694ed1de3f0b2be76f834/18868110120.pdfIn PDF document text
    • https://lesfeesdelhetre.fr/upload/files/24138935356.pdfIn PDF document text
    • http://www.yevres.fr/ckfinder/userfiles/files/pikex.pdfIn PDF document text
    • http://wanyuantemple.tw/userfiles/file/80014181562.pdfIn PDF document text
    • http://asdgolfclubtoscana.com/writable/public/userfiles/file/46219532953.pdfIn PDF document text
    • http://easyliveconstruction.com/ci/userfiles/files/12776314541.pdfIn PDF document text
    • http://www.introspekta.si/ckfinder/ckeditor_uploaded_files/files/84401802126.pdfIn PDF document text
    • https://hsegroup.ru/wp-content/plugins/super-forms/uploads/php/files/srqdtsinlnb26l5p6bukk7kec5/72290828007.pdfIn PDF document text
    • https://mobilaide.com/upload/editor/file/zogekosag.pdfIn PDF document text
    • http://paynechapelduquesne.org/clients/9/9b/9b910c66cef3ae2d1bb1fd5804160a19/File/36969044022.pdfIn PDF document text
    • http://starlightskiothon.ca/clients/4/44/44db284a3a4a6a3f34f8f2fa71918f98/File/nasesef.pdfIn PDF document text
    • http://asbu.net/uploads/FCK_files/file/zogisoneduxowenudo.pdfIn PDF document text
    • http://jeugdopdewetenschapsagenda.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16095baee27d33---14683735524.pdfIn PDF document text
    • http://autobedrijvenindex.nl/images/uploads/76745298737.pdfIn PDF document text
    • https://birudongker.com/contents//files/galejipebexotojoxulo.pdfIn PDF document text
    • http://fxlcd.com/upload/file/36275101645.pdfIn PDF document text
    • https://newat.ru/wp-content/plugins/super-forms/uploads/php/files/a2b8dda6d8e5c9940b9a5d10f053f33e/96216383162.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/6naE_Nh8_CY/uplcv?utm_term=que+es+un+estudio+de+mercado+libros+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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000de5a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE5A 19368 bytes
SHA-256: cbe3106499426a525126ba7ae4a7a123852954f21af043d558b403d60eaca3d6
font_01_sfnt_off00010f42.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10F42 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012759.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12759 11080 bytes
SHA-256: 8f379c3ffae9eff90cd4116ef7d3f7314510e1d29f3b751e982c852bc0dd4f21

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