Malicious PDF — malware analysis report

Static analysis result for SHA-256 e73851cda75fb82d…

MALICIOUS

PDF

74.0 KB Created: 2021-06-06 06:38:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-14
MD5: 98a3da114767f05d722f2c760381be0f SHA-1: d72e29108e5ee7780de5409a565fb76c5a119469 SHA-256: e73851cda75fb82de51de5abadded16d027d31da7e1c605ed7deaf5b3f84131d
156 Risk Score

Malware Insights

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

This PDF file is identified as malicious by ML classifiers and ClamAV, indicating a phishing or trojan payload. It contains numerous links to external PDFs hosted on compromised WordPress sites and disposable domains, suggesting a link farm designed to distribute malicious content. The embedded URLs and link farm structure strongly suggest an attempt to trick users into downloading further malicious files, likely as part of a phishing campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://krisoc.ru/uplcv?utm_term=russian+grammar+pdf+download PDF link annotation
    • http://windcampus.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606ea1c1a9a2f---kukivurexoparaz.pdfIn PDF document text
    • http://www.holderit.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a6f2b9984d6---dogiwimux.pdfIn PDF document text
    • https://amitadevnani.com/userfiles/file/wuvejinade.pdfIn PDF document text
    • http://www.combatsim.eu/wp-content/plugins/formcraft/file-upload/server/content/files/1609b2ed583184---malanesasopinawutigipeli.pdfIn PDF document text
    • http://www.grupohk.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160afc19928b13---52245347426.pdfIn PDF document text
    • https://www.conkite.com/wp-content/plugins/super-forms/uploads/php/files/2e9aa05654a49c338c8f4c0eb83e2d59/48494057503.pdfIn PDF document text
    • http://novichiha.ru/pic/file/wiserodab.pdfIn PDF document text
    • http://logiccpacma.com/ckfinder/userfiles/files/49806588056.pdfIn PDF document text
    • https://blsautomation.com/ckfinder/userfiles/files/70005867802.pdfIn PDF document text
    • https://unosms.us/userfiles/file/90111007881.pdfIn PDF document text
    • http://humanitool.ru/userfiles/file/57030419621.pdfIn PDF document text
    • https://simondaulte.com/ckfinder/userfiles/files/fifirebaku.pdfIn PDF document text
    • https://ehblending.com/wp-content/plugins/super-forms/uploads/php/files/b353171204b0bf5730940326d93ce563/16876515291.pdfIn PDF document text
    • http://premiumresourcing.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609d00c136778---robedagabevepe.pdfIn PDF document text
    • http://labcoop-jsc.com/wp-content/plugins/super-forms/uploads/php/files/1959up1ljdcn30aim7s229hpj3/39205607380.pdfIn PDF document text
    • https://www.asahinafunnels.com/wp-content/plugins/super-forms/uploads/php/files/or2sp1rqsqm2lh7jbqhsgs3usp/fuxusugudinej.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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_off0000dc12.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC12 5460 bytes
SHA-256: fe536db26d5524a550ca99f9663387d6ca0cc294ff85f0a513bdca53fc457af9
font_01_sfnt_off0000eea8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEEA8 13964 bytes
SHA-256: 46dddb12f99d735944c5b624093120620226aa48c65383237e5b5f1ba4cf78f7