Malicious PDF — malware analysis report

Static analysis result for SHA-256 3c9762b62611c9d1…

MALICIOUS

PDF

92.9 KB Created: 2021-09-05 09:44:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: fdec49264f5f18c0cfb6b7c1aa1cd51d SHA-1: 0b28b66b5a4b89ad30f155f86a6f23d8feee39db SHA-256: 3c9762b62611c9d157606df13d7decb539534560feb98e2e2641e798fac5809a
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous external URIs and links to compromised websites, suggesting it is used as a link farm to redirect users to potentially malicious content. The presence of PDF-specific heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' further supports this, indicating a tactic to obscure the true destination or leverage compromised infrastructure. No scripts were extracted, but the overall structure points to a phishing or malware distribution lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9905

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://laborke.ru/uplcv?utm_term=fisiologia+del+sistema+respiratorio+veterinaria+pdf PDF link annotation
    • https://bouwservicewinthagen.nl/userfiles/image/file/nizevesejaxozoxarileru.pdfIn PDF document text
    • http://kaymccarthy.com/immagini/file/tupepipati.pdfIn PDF document text
    • http://smit-electronic.hr/upload/datoteke/dapegogelu.pdfIn PDF document text
    • https://www.helpforbusymums.com/wp-content/plugins/super-forms/uploads/php/files/696e5ffaedbf906327fa3d7fcafed9fb/rezowopulebusukufusijajox.pdfIn PDF document text
    • http://artechq8.com/beta/uploads/files/89408668481.pdfIn PDF document text
    • http://uptownchantilly.com/uploads/files/69544717672.pdfIn PDF document text
    • http://bbgannualseminar.com/clients/6/60/607ac775fa755cf068047886b2bbe24d/File/76772274192.pdfIn PDF document text
    • http://www.sparkprototypes.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a8980f35bc9---14761036470.pdfIn PDF document text
    • https://yziact.fr/wp-content/plugins/super-forms/uploads/php/files/ot7n9tmb2l48i2hen9c76ibahh/37306875013.pdfIn PDF document text
    • http://divodizain.ru/ckfinder/userfiles/files/69003278922.pdfIn PDF document text
    • http://www.jfac.kr/ckfinder/userfiles/files/32452984730.pdfIn PDF document text
    • http://moveisgarciadigital.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160a905a1eabcb---gesilalu.pdfIn PDF document text
    • https://chemasan.lu/userfiles/files/94175004642.pdfIn PDF document text
    • http://intechsol.kz/wp-content/plugins/formcraft/file-upload/server/content/files/160ab8d6e33d0e---55284190609.pdfIn PDF document text
    • http://megat.pl/uploaded/fck_files/file/nifovokoketemijoxebodomu.pdfIn PDF document text
    • https://gelblighting.com/userfiles/files/vivumuboxu.pdfIn PDF document text
    • https://stcatherine.ac.ug/wp-content/plugins/formcraft/file-upload/server/content/files/1610066d449890---69628738443.pdfIn PDF document text
    • http://breakevenpoint.pl/uploads/editor/file/92964991416.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607f2d3b5e86f---53699828482.pdfIn PDF document text
    • http://jiab.net/userData/board/file/81163509355.pdfIn PDF document text
    • http://www.miamiairportlimo.net/wp-content/plugins/formcraft/file-upload/server/content/files/160cd0b8b9b4a6---39958148164.pdfIn PDF document text
    • http://hengtongrongshang.com/jingkelun/userfiles/files/20210819044429.pdfIn PDF document text
    • https://jamiatulbanat.in/wp-content/plugins/formcraft/file-upload/server/content/files/16075328ce3f8d---43818161419.pdfIn PDF document text
    • http://homeopathyhongkong.org/files/lasogotomod.pdfIn PDF document text
    • https://gea99.com/ckfinder/userfiles/files/galipexidutifebifinude.pdfIn PDF document text
    • https://wlao.on.ca/wp-content/plugins/super-forms/uploads/php/files/8eca3c103c444cf06f0723fe9196303c/95430270830.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://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_off000105b5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x105B5 10884 bytes
SHA-256: f0e1aaee654bb6517660e22dece1cc27def436094b3edd93763ebb173c63cc0f
font_01_sfnt_off00011ea8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11EA8 18076 bytes
SHA-256: 27db87d2aad7b6ee7c40c3c19a0d9c05e6ca78c2b8cc8b1bc254d36d8bf5c921
font_02_sfnt_off00014ce9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14CE9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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