Malicious PDF — malware analysis report

Static analysis result for SHA-256 a83dc73d1be50415…

MALICIOUS

PDF

82.2 KB Created: 2021-09-15 13:32:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 974457cb390d2e934251b7b1c895812d SHA-1: 4cea8aa74da612c145367fed471219d58027b54b SHA-256: a83dc73d1be5041584bbd070b2a92776165608f0e92305c059962cd14b33db7c
66 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs pointing to various PDF files hosted on different domains, indicating a link farm. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' strongly suggests this is the primary purpose. While no scripts were extracted, the ML classifier flagged the PDF as malicious, and the structure implies it's part of a larger distribution or SEO manipulation scheme, likely initiated via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

Heuristics 4

  • 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://www.rockandroll.blog.br/wp-content/plugins/super-forms/uploads/php/files/hsupo88qftk1hss7a6mdtjptm2/mijolumibu.pdf In PDF document text
    • https://global-brand.net/userfiles/files/nosakeladasiloninipala.pdfIn PDF document text
    • https://www.koreayokogawa.com/ckfinder/userfiles/files/31349906656.pdfIn PDF document text
    • http://bluecars.pl/userfiles/file/pedudimikoja.pdfIn PDF document text
    • http://bsa-billiard.by/images_from_html_editor/file/wogaworoponibewatif.pdfIn PDF document text
    • https://cakesandcupcakes.net/userfiles/files/sedebemudizi.pdfIn PDF document text
    • http://sicilalluminio.it/userfiles/files/35948774329.pdfIn PDF document text
    • http://goldenstarhotel.vn/images/uploads/files/71217077049.pdfIn PDF document text
    • https://dutchfansitenetwork.nl/ckfinder/userfiles/files/66871333613.pdfIn PDF document text
    • http://siripanyalamphun.com/user_img/files/suruxawulowefude.pdfIn PDF document text
    • http://mislenyiallatorvos.hu/userfiles/file/rajosapoxujiwurubonarej.pdfIn PDF document text
    • http://vietsaovang.com/uploads/userfiles/file/fosebigu.pdfIn PDF document text
    • https://zlato-stribro-investice.com/upload/files/65783408295.pdfIn PDF document text
    • http://hockjoohin.com/admin/uploads/file/96476291773.pdfIn PDF document text
    • http://kingsfinancialconsulting.com/userfiles/file/wakofijeke.pdfIn PDF document text
    • http://coolscape.info/images/files/51368834623.pdfIn PDF document text
    • http://kfnmdg.com/upfolder/e/files/20210913232026.pdfIn PDF document text
    • http://koovappadyscb.com/ckfinder/userfiles/files/54510583096.pdfIn PDF document text
    • http://ty-universe.com/image/files/20210906_091816.pdfIn PDF document text
    • http://michelesherrinlaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/mibufakinewenoluvu.pdfIn PDF document text
    • https://inprovitchile.com/ckfinder/userfiles/files/66019877112.pdfIn PDF document text
    • http://claudiodauelsberg.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1613c3fc413526---zedinojozamak.pdfIn PDF document text
    • http://resortvillairene.it/userfiles/files/80263746533.pdfIn PDF document text
    • http://musthighschool.mn/ckfinder/userfiles/files/6950476753.pdfIn PDF document text
    • http://greece-ex.com/images/blog/file/webesevozewajenedakavuzo.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=candy+crush+soda+saga+apk+hackPDF 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_off0000dbde.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDBDE 10764 bytes
SHA-256: 36d2d1466b5227bee8adfd19ed2aa7ea29e2a8e6054edfbdc9ebfc68dea93317
font_01_sfnt_off0000f466.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF466 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010c78.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C78 18232 bytes
SHA-256: e2fed7e10a569ac25b59c51a6fb9f33c6b0abd552ba236aa3921c9b41cb14418

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