Malicious PDF — malware analysis report

Static analysis result for SHA-256 b73b413c8bfd55fc…

MALICIOUS

PDF

79.9 KB Created: 2021-09-19 18:12:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 476aadecf29c75fef9472f2d5c7b59f1 SHA-1: 0205d0e17bf17fc144cfb2d5365fd50a1ce77fa0 SHA-256: b73b413c8bfd55fc905214f8c4b83cda74554e3ecd6706411fd2f3054429ca38
156 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous URLs pointing to compromised WordPress sites, likely intended to lure users to malicious content. The ML_NYX_PDF_MALICIOUS and CLAMAV_DETECTION heuristics strongly support the malicious classification.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://primeodontorj.com/wp-content/plugins/super-forms/uploads/php/files/ab0fbaf24a79bf9e648dd0c1c6c2d6d3/laximuxazikonu.pdf In PDF document text
    • https://wcdt.co.th/wp-content/plugins/super-forms/uploads/php/files/vh4vfqleecgjus4a907fkqs6vo/54941707858.pdfIn PDF document text
    • http://oryginalnedekoracje.pl/userfiles/file/sofamufidapividipuzisud.pdfIn PDF document text
    • http://opakowania-loga.pl/zdjecia/fotki/file/sisosaxusupev.pdfIn PDF document text
    • http://suachuadienlanhhoaphat.com/hinhanh_fckeditor/file/26262186000.pdfIn PDF document text
    • http://studiotecnicobonoli.com/userfiles/files/92443481456.pdfIn PDF document text
    • http://alhambra.kopanramen.com/uploads/files/kajogevibowaf.pdfIn PDF document text
    • https://inchiriereelicoptere.ro/wp-content/plugins/formcraft/file-upload/server/content/files/161444be5bb830---duridazizupulanudusunejaj.pdfIn PDF document text
    • https://vmkstroi.ru/wp-content/plugins/super-forms/uploads/php/files/b477b0bf4020e5ff68d2c78374334141/ketukoratoraxuvekudow.pdfIn PDF document text
    • https://shiokuda2.com/contents/files/25310349319.pdfIn PDF document text
    • http://ustunongel.com/image/files/17574251712.pdfIn PDF document text
    • http://reclaimsplus.com/wp-content/plugins/super-forms/uploads/php/files/e0c94f532f10dfc989819af96ecd799e/63972968767.pdfIn PDF document text
    • http://hoaisonland.vn/upload/files/10526279174.pdfIn PDF document text
    • http://happyland-nsk.net/ckfinder/userfiles/files/68610558852.pdfIn PDF document text
    • http://mail.me.ntou.edu.tw/ckfinder/userfiles/files/20210918_021021.pdfIn PDF document text
    • http://simonide.org/userfiles/file/87144934538.pdfIn PDF document text
    • https://medpressa.ru/files/file/76547711066.pdfIn PDF document text
    • https://pnlcoach.com/misc2/file/In PDF document text
    • http://bostoncake888.com/UserFiles/files/dexupifiwokobewuxiketunav.pdfIn PDF document text
    • http://vdavloeren.be/userfiles/files/fileguwuxojumoved.pdfIn PDF document text
    • http://tea-ra.com/user_data/upload/save_image/files/76028834082.pdfIn PDF document text
    • https://tl-systems.hu/files/files/ketofovivi.pdfIn PDF document text
    • https://tommytest.dish1314.com/data/html_editor/files/36165260721.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BkSY9tpko7c/uplcv?utm_term=how+to+draw+darth+vaderPDF 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_off0000d59c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD59C 10080 bytes
SHA-256: 0bf288cd177aad68047a1e62ab448fd393f9439600336d37e788725b80112e8f
font_01_sfnt_off0000ec29.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC29 17876 bytes
SHA-256: cf1903edf52d22c9ce865d7cd8959e1e25dc4373af2ea521fecf25f5e64ad09e
font_02_sfnt_off00011a42.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11A42 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1