Malicious PDF — malware analysis report

Static analysis result for SHA-256 28f35313cdebe2a5…

MALICIOUS

PDF

86.4 KB Created: 2021-09-09 08:56:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-29
MD5: 1006a44120575f8781937106fb0e222c SHA-1: ac8213f61351e13d5022efab98a2948541c9e14d SHA-256: 28f35313cdebe2a55eee0c41ff27bff3e55b8dfb520b25ac62c13f74f84001ae
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as a malicious PDF by ClamAV and an ML classifier. It contains numerous external URIs, with many pointing to disposable hosting, indicating a link farm or redirection scheme. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic specifically flags this behavior. While no scripts were extracted, the presence of many external links suggests the PDF's primary function is to redirect users to potentially malicious websites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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 https://stw-nowogard.pl/download/file/39539894270.pdf In PDF document text
    • http://letsbelegal.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/15313284977.pdfIn PDF document text
    • https://jasz-pap.hu/UserFiles/file/64564476.pdfIn PDF document text
    • https://lionkingbali.com/uploads/file/51626282620.pdfIn PDF document text
    • http://bikaji.zohukum.com/ckfinder/userfiles/files/74960043038.pdfIn PDF document text
    • http://agnieszkapawlik.com/userfiles/file/65062969808.pdfIn PDF document text
    • http://zssadkowice.pl/pliki/17398248334.pdfIn PDF document text
    • https://hinodanang.com/uploads/image/files/rasoka.pdfIn PDF document text
    • https://varbackaforskola.se/ckfinder/userfiles/files/datinilusatigatebi.pdfIn PDF document text
    • http://star-transform-moscow.ru/uimg/files/8664957274.pdfIn PDF document text
    • http://aow.infogestnet.it/ckfinder/userfiles/files/35147925894.pdfIn PDF document text
    • https://gikguamerica.com/userfiles/file/tatevobipewe.pdfIn PDF document text
    • https://eownauto.com/uploadpic/files/bodusod.pdfIn PDF document text
    • http://lerucherdesanges.fr/userfiles/file/wajosusatokikugikewi.pdfIn PDF document text
    • http://zlzljc.com/uploadfile/file///2021090606452210.pdfIn PDF document text
    • http://usatovl.ru/upload/fckeditorfile/vemapezimegodutederi.pdfIn PDF document text
    • http://kammed.com/userfiles/file/99088477092.pdfIn PDF document text
    • https://phuquiland.com/upload/files/99071340486.pdfIn PDF document text
    • https://evpersoneli.net/ev-personeli/file/dinaparujafope.pdfIn PDF document text
    • http://youandisagenix.com/ckfinder/userfiles/files/83066360646.pdfIn PDF document text
    • https://szabobuszberles.hu/files/files/22297077690.pdfIn PDF document text
    • https://vietrocknet.org/app/webroot/img/files/vifeludumevaxaw.pdfIn PDF document text
    • https://igk-lilienthal.de/downloads/46024660171.pdfIn PDF document text
    • http://wingprocess.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/sedilafakezowosoxowotine.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/A3Ryygt5BCM/uplcv?utm_term=keyword+io+toolPDF 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_off0000efe7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFE7 10000 bytes
SHA-256: bf4d0fbf9c5c896d6921ff9d24f3f316dfedcba45cc8702786e73855f451420b
font_01_sfnt_off00010634.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10634 17800 bytes
SHA-256: 83ce1fc57d1aa7d850a386091c6f118d18879422a1756d25573c169c19a538f2
font_02_sfnt_off00013406.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13406 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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