Malicious PDF — malware analysis report

Static analysis result for SHA-256 831c82afcb00d444…

MALICIOUS

PDF

76.5 KB Created: 2021-09-16 12:21:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-21
MD5: 71b9d9e4789cb101775c9112700cec66 SHA-1: e3910d648ab8447d85d06cd502c1650d6034debb SHA-256: 831c82afcb00d44445551975f192102eee06a7297537a6d2722703dcee2d3f39
126 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, with a high heuristic score indicating it functions as a link farm. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware distribution via the linked PDFs. The document body is unreadable, but the presence of many links points to an attempt to redirect the user to external, potentially malicious, content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9840

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.ddu-hk.cz/ckfinder/userfiles/files/xaludusewumabutemidas.pdf In PDF document text
    • http://giadinhlaurenso.org/upload/files/guvirijolovape.pdfIn PDF document text
    • http://crystaltrade.hu/data/file/fejurogigusugekowuze.pdfIn PDF document text
    • http://simonide.org/userfiles/file/68010072130.pdfIn PDF document text
    • https://mingyi-lock.com/data/file/userfiles/files/76608926857.pdfIn PDF document text
    • http://anshan56.cn/userfiles/file/16313896721206647738.pdfIn PDF document text
    • http://www.yeosung21.or.kr/ckfinder/userfiles/files/1630635360.pdfIn PDF document text
    • http://lawcab.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1612f629c2adfa---xifemadipebomuluv.pdfIn PDF document text
    • http://saatgaamkansarasamaj.com/admin/uploads/files/gozupuzizizul.pdfIn PDF document text
    • http://drairtools.com/ckfinder/userfiles/files/sirozolupanomosofemuxov.pdfIn PDF document text
    • http://robertfeinberglaw.com/images/edit_images/file/jutozatusifepa.pdfIn PDF document text
    • http://topnotchimports.com/ckfinder/userfiles/files/41092542253.pdfIn PDF document text
    • http://ncteonline.com/userfiles/file/zosibu.pdfIn PDF document text
    • https://tonerihned.cz/userfiles/file/sajez.pdfIn PDF document text
    • https://rusepress.com/uploads/wysiwyg/files/gelopixexegoba.pdfIn PDF document text
    • https://venus-forever.com/image/files/36778803046.pdfIn PDF document text
    • https://fallsplat.se/bildbank/file/sefusiw.pdfIn PDF document text
    • https://www.grdr.org/paidel/ckfinder/userfiles/files/migok.pdfIn PDF document text
    • http://cen7dias.es/userfiles/files/97176610458.pdfIn PDF document text
    • http://ct-tci.com/cttax/userfiles/files/5263653184.pdfIn PDF document text
    • http://tachikawa-derma.biz/ckfinder/userfiles/files/fuxunibewevovolad.pdfIn PDF document text
    • https://anandamsanyal.com/userfiles/file/lemawale.pdfIn PDF document text
    • http://beastyenergy.com/userfiles/file/mefoterixi.pdfIn PDF document text
    • http://gpmpoolandspa.com/ckfinder/userfiles/files/55151481614.pdfIn PDF document text
    • http://robvancampen.nl/userfiles/file/22219330279.pdfIn PDF document text
    • http://matrix-corporation.com/upfiles/editor/files/kuwidulazofuxiru.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/ngfLrbzwjls/uplcv?utm_term=grundriss+zeichnen+app+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_off0000c57f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC57F 10668 bytes
SHA-256: 95ccc09811b83e0532d4355def71da452db53313bdf69b575aa5b9c345ffcda5
font_01_sfnt_off0000dddb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDDDB 18468 bytes
SHA-256: 245ccc8eeca9f63d85e193827cbe36853610ad75067105f4e351be6af9b37572
font_02_sfnt_off00010c32.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C32 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1