Malicious PDF — malware analysis report

Static analysis result for SHA-256 3bc13968224d9d6e…

MALICIOUS

PDF

74.8 KB Created: 2021-09-16 09:54:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 0c2bd36595f8c2ae8fcaa2fd58036d02 SHA-1: 323381e6015a80abb2ef3fb8b6ad223574c072eb SHA-256: 3bc13968224d9d6ec3845e29ce9ef47c4d5f80dbb3002e4d78852eb1ea01a07e
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected by ClamAV as Pdf.Phishing.Trojan and flagged by an ML classifier, indicating malicious intent. The PDF contains numerous embedded URLs, many of which point to other PDF files, suggesting a link farm designed to obscure the ultimate destination. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' further supports this, indicating a technique to distribute malicious content. While no scripts were explicitly extracted, the nature of the embedded URLs and the detection names suggest a phishing or malware distribution vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://expobar.vn/app/webroot/files/images/pages/files/9693365763.pdf In PDF document text
    • http://amkchem.com/upload/files/bivugoripovariratugaxexis.pdfIn PDF document text
    • https://isosklo.cz/uploads/38646559494.pdfIn PDF document text
    • http://studiopetrilli.it/userfiles/files/tazowixixibufoberazewagu.pdfIn PDF document text
    • http://aucoindeshalles.com/menu/file/pomaxemoretubejuweri.pdfIn PDF document text
    • https://www.bevillelecomte.com/ckfinder/userfiles/files/juxidufexexagazenik.pdfIn PDF document text
    • http://cjcounsel.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/57156204374.pdfIn PDF document text
    • http://darangyi.com/userData/board/file/33654764313.pdfIn PDF document text
    • http://qigong.ru/userfiles/file/99276305268.pdfIn PDF document text
    • http://drukarnia-skawina.pl/app/webroot/media/files/63301224649.pdfIn PDF document text
    • https://generalaudit.pl/eurostyl/photos/file/mudebepibuvudixikopujik.pdfIn PDF document text
    • https://aquafilling.com/userfiles/file/34184080104.pdfIn PDF document text
    • http://faptvmedia.com/userfiles/file/99899410252.pdfIn PDF document text
    • https://unaizahic.com/Files/files/xidiravasilalobigi.pdfIn PDF document text
    • http://forepic.com/_UploadFile/Images/file/vojutegidudiwuvatedejan.pdfIn PDF document text
    • http://iamsoldierfit.com/wp-content/plugins/formcraft/file-upload/server/content/files/16141b8b68c059---93639162643.pdfIn PDF document text
    • http://jinyudachem.com/upload/files/betizinaziw.pdfIn PDF document text
    • http://teplorium.su/userfiles/file/bimuj.pdfIn PDF document text
    • http://laptopcuhaiphong.vn/upload/files/31694185242.pdfIn PDF document text
    • https://dazhonghua1688.com/ckfinder/userfiles/files/61744718334.pdfIn PDF document text
    • http://togclick.com/media/userFckfiles/file/sobimokupimasop.pdfIn PDF document text
    • http://zensushidanapoint.com/uploads/files/xojigosazijat.pdfIn PDF document text
    • https://editora-arara-azul.com.br/site/admin/ckfinder/userfiles/files/46279691340.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=drawing+animation+app+for+androidPDF 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_off0000c178.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC178 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d98f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD98F 10580 bytes
SHA-256: 4998c7c08519664c068587835e9054e4e8161ea1a8f212e65ada6be696ec15f9
font_02_sfnt_off0000f177.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF177 17444 bytes
SHA-256: 6655444848a145d05f7e4ac02570b9c9a29d44d0993612b779ea106527207301