Malicious PDF — malware analysis report

Static analysis result for SHA-256 81436d93a3288e5c…

MALICIOUS

PDF

80.3 KB Created: 2021-09-19 07:16:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: dd68c09b4d973f297793a0a54c318f3d SHA-1: fdd19761f645a8103db6094f97323c80895d9f44 SHA-256: 81436d93a3288e5c011b0d295e6baf0008b224c507e70aaedf82ccd75d5dd75d
126 Risk Score

Malware Insights

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

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous embedded URLs pointing to external PDF files, suggesting a link farm or redirection mechanism. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, indicating a pattern of using disposable hosting for these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9833

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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.bash.cl/media/file/pepaluniwirubebokotalir.pdf In PDF document text
    • https://fiberglasssupplydepot.com/userfiles/files/fulukabetuzuxodapifubojuw.pdfIn PDF document text
    • http://guanzhuli.com/userfiles/file/67015498485.pdfIn PDF document text
    • http://sportingfoundation.com/uploads/file/tomidafegisolefen.pdfIn PDF document text
    • http://hotelrefah4ter.ir/basefile/hotelrefah4terir/files/vabitemedibokonunupu.pdfIn PDF document text
    • http://handsonmontessoripk.com/userfiles/files/ripinulofitobi.pdfIn PDF document text
    • https://suativisamsungtaihanoi.net/upload/files/xasisekupufavub.pdfIn PDF document text
    • http://discoveryenglish.org/wp-content/plugins/formcraft/file-upload/server/content/files/161414324cf015---95086442723.pdfIn PDF document text
    • https://latework.cz/soubory/zajetuxatev.pdfIn PDF document text
    • http://jts-electrical.co.uk/ckfinder/userfiles/files/83282028697.pdfIn PDF document text
    • http://intertravel.hu/_user/file/88076081814.pdfIn PDF document text
    • https://mangonebike.com/uploads/file/gizexomekak.pdfIn PDF document text
    • https://www.gico.ge/ckfinder/userfiles/files/materubiwatilile.pdfIn PDF document text
    • http://liebherr-tr.com/userfiles/file/8587363875.pdfIn PDF document text
    • http://pwr-tech.ru/userfiles/file/ripojimuzovesu.pdfIn PDF document text
    • http://gibisch.com/files/files/66029612409.pdfIn PDF document text
    • http://bong-dem-long.org/upload/editor/files/kerunolibolotade.pdfIn PDF document text
    • http://gerd-pollak.de/userfiles/file/wanetakip.pdfIn PDF document text
    • http://ilkemymm.com/image/files/gizagegudigetupojaxudoreb.pdfIn PDF document text
    • https://cursosadistanciayonline.com/medios/files/74389114001.pdfIn PDF document text
    • https://typeone.com.my/ckfinder/userfiles/files/ranevovejinavowuxufe.pdfIn PDF document text
    • http://mrcubezpieczenia.pl/app/webroot/media/files/56686439780.pdfIn PDF document text
    • http://eros-arena.de/eros/userfiles/file/pivowu.pdfIn PDF document text
    • http://www.ks-klinika.ru/ckfinder/userfiles/files/wusixulunatub.pdfIn PDF document text
    • https://hohsingfiber.com/ufiles/files/bonepanusuzatusedal.pdfIn PDF document text
    • http://ptichile.cl/userfiles/file/kigesagovomuwuwesasutaz.pdfIn PDF document text
    • https://www.akilciilacdernegi.com/ckfinder/userfiles/files/45295098859.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BkSY9tpko7c/uplcv?utm_term=how+turn+off+developer+modePDF 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_off0000d73e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD73E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ef50.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF50 17464 bytes
SHA-256: dff3a392b453dddb64e51f32931bf47b5313999f3b3406d78c205c73a2f10f72
font_02_sfnt_off00011be8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11BE8 10480 bytes
SHA-256: 8ce1c1c5958961624a46a8b06344efcae7830e7b20e40a155b27c03391236c2c