Malicious PDF — malware analysis report

Static analysis result for SHA-256 87f8b57e386439ff…

MALICIOUS

PDF

74.4 KB Created: 2021-06-10 10:26:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-14
MD5: 65870561a102a42762ad1e3b12f3d8ba SHA-1: 74b5372b220b95bbcbc14ea195ebf3c76607c858 SHA-256: 87f8b57e386439ff564536b19d0b31de6d36c2cd58d08bc4d2c2269135a7db2d
156 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous links, many pointing to compromised CMS upload directories, suggesting a link farm designed to distribute malware. The document body, though heavily obfuscated, appears to be a lure for a 'worksheet with answers PDF', aligning with phishing or social engineering tactics.

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://ketchas.ru/uplcv?utm_term=one+to+one+function+worksheet+with+answers+pdf PDF link annotation
    • https://www.lamuccacompany.com/wp-content/plugins/super-forms/uploads/php/files/1b189ea641c1f02cc2b1af3943194100/66634323939.pdfIn PDF document text
    • https://asiaviews.org/wp-content/plugins/super-forms/uploads/php/files/95iig7bjg75hdk3ts1muf5i690/dovizulesuke.pdfIn PDF document text
    • http://hokeypokeychallenge.com/clients/7/77/77ac66e313b6cb4bf602f1678accca72/File/44557420339.pdfIn PDF document text
    • https://g3az.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607103648b82a---60620191790.pdfIn PDF document text
    • https://tlproduct.com/userfiles/file/lolotoj.pdfIn PDF document text
    • http://www.klpreschool.com/wp-content/plugins/formcraft/file-upload/server/content/files/16085313c6c0e5---13910124030.pdfIn PDF document text
    • https://simovi.mx/wp-content/plugins/formcraft/file-upload/server/content/files/160a005546e88e---wakejiposavatasifajokakuf.pdfIn PDF document text
    • http://www.sg-callenberg.de/wp-content/plugins/formcraft/file-upload/server/content/files/160aad87e8a898---40623387562.pdfIn PDF document text
    • http://www.nandomoraes.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1608d90996467b---lanimewiviguzarif.pdfIn PDF document text
    • http://www.fliesen-brill.de/wp-content/plugins/formcraft/file-upload/server/content/files/160a4bb171be56---roxuvikenisavolupuzud.pdfIn PDF document text
    • https://neavocats.com/wp-content/plugins/super-forms/uploads/php/files/cae1505efe0d3f0143eb1e89c218e824/sobotijuliladomatabufe.pdfIn PDF document text
    • http://www.justgiveahand.org/wp-content/plugins/formcraft/file-upload/server/content/files/160a0d805430ec---73786485642.pdfIn PDF document text
    • https://arket.io/wp-content/plugins/super-forms/uploads/php/files/sbhhe6p1sn0q3nbqhfunlj9k5p/83333983149.pdfIn PDF document text
    • http://erfolgsapp.de/wp-content/plugins/formcraft/file-upload/server/content/files/160b741f12687b---pezefakeketasufepovel.pdfIn PDF document text
    • http://dabien.co.kr/wp-content/plugins/formcraft/file-upload/server/content/files/1607e31f3c68dc---32380646061.pdfIn PDF document text
    • http://akcjonariusz.com/UserFiles/file/zifot.pdfIn PDF document text
    • https://ailani.org/wp-content/plugins/super-forms/uploads/php/files/d9772838fd73da5ca9f200db71a027c3/99523374655.pdfIn PDF document text
    • https://cottonweb.net/userfiles/file/xebodutikujesajawujaj.pdfIn PDF document text
    • https://www.dazzlingdecor.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160925ea948775---76877034786.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_off0000e215.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE215 5396 bytes
SHA-256: 0524dadaeddd895776a597255a5c1d51845bf3fa1dc7b3e96ed9d32921ec159a
font_01_sfnt_off0000f482.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF482 11532 bytes
SHA-256: a1ca8fdbc845577274da5bbdb84f30c328cd0aa6e70d03d19eca8a7d1b42da60

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