Malicious PDF — malware analysis report

Static analysis result for SHA-256 43926a86eaeab5ae…

MALICIOUS

PDF

85.6 KB Created: 2021-03-16 04:32:59 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-22
MD5: 900e8aa2f9118d8f9cbcddf4a503794b SHA-1: 88fad2803ca2712aaabd38b0b98bf613fff4382e SHA-256: 43926a86eaeab5aea96d1c7bec1ed884955abc6c474b8b7de8d3983ef64b0235
126 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, with a primary focus on directing users to 'kuzutuzo.ru'. Heuristics indicate this is a link farm hosted on disposable infrastructure, designed to obscure the true malicious intent. The ML classifier and ClamAV detection strongly suggest malicious content, likely a phishing lure or a downloader.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://kuzutuzo.ru/wix?keyword=big+ideas+math+geometry+pdf PDF link annotation
    • https://mitenipup.weebly.com/uploads/1/3/4/3/134363071/597146.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4468843/normal_5fc5b0f0f388d.pdfIn PDF document text
    • https://lelobetiladafan.weebly.com/uploads/1/3/4/4/134497055/6540207.pdfIn PDF document text
    • https://rupasofo.weebly.com/uploads/1/3/4/8/134892789/jilosikemeju_gixabidepupibi_midolenidofel.pdfIn PDF document text
    • http://kutufirix.iblogger.org/77962226267.pdfIn PDF document text
    • http://paksorond.xyz/62247276411qevuh.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4456687/normal_5ffbf0e990b55.pdfIn PDF document text
    • https://fujimerikav.weebly.com/uploads/1/3/4/3/134307110/9616356.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4370057/normal_603e2e1f1d7d2.pdfIn PDF document text
    • https://guditeni.weebly.com/uploads/1/3/4/5/134529862/8183371.pdfIn PDF document text
    • http://italywow.pro/47230848197j5r8i.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/mubemutolewe/gofabej.pdfIn PDF document text
    • http://robebiwasufilu.epizy.com/kamisipu.pdfIn PDF document text
    • https://s3.amazonaws.com/piwanisaj/adobe_audition_cc_2017_direct.pdfIn PDF document text
    • http://fipenalexaxa.epizy.com/56969652082.pdfIn PDF document text
    • https://s3.amazonaws.com/fomudebipefasu/barbie_girl_video_song_hd.pdfIn PDF document text
    • https://s3.amazonaws.com/sabegokek/16184585931.pdfIn PDF document text
    • http://melumudinev.epizy.com/magic_rush_equipment_guide.pdfIn PDF document text
    • 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00010daf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10DAF 5576 bytes
SHA-256: 0837a37beb2c32dc04c2514222c840dda15edb208baa455bfb31de1d13e79afb
font_01_sfnt_off0001208a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1208A 11580 bytes
SHA-256: 9199d57c3b9d60bfea3c9a5f5719d6d6393e2efd37ec32e5285892ed0597d981

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