Malicious PDF — malware analysis report

Static analysis result for SHA-256 d15861e452eab170…

MALICIOUS

PDF

69.0 KB Created: 2021-05-31 21:16:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-20
MD5: 3d53c0833ee4ad62fc1edca8d49778b2 SHA-1: bb4392e65c9ca55c235877809d32e4cb820334a8 SHA-256: d15861e452eab170f2d7ef31c11dbdcc23f4322542510a6ad5ed74b3db005b90
126 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous external URIs, with one prominent URL pointing to 'laborke.ru' which is associated with a link farm and disposable hosting. The document body, though heavily obfuscated, suggests a lure related to educational worksheets, likely to trick users into clicking malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 https://laborke.ru/pbw?utm_term=compound+words+worksheet+grade+1+pdf PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4465564/normal_605d82d7c881e.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4384152/normal_601708310f266.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://bupataved.pbworks.com/w/file/fetch/144421263/hsv_eraser_really_work.pdfIn PDF document text
    • http://mudowomuxexo.pbworks.com/w/file/fetch/144422592/am_pm_ka_full_form_kya_hoga.pdfIn PDF document text
    • http://dawijunegolo.pbworks.com/w/file/fetch/144423324/tutorial_737_800_ng_pmdg.pdfIn PDF document text
    • http://gajufabeke.pbworks.com/w/file/fetch/144423063/how_much_do_designers_charge_for_a_logo.pdfIn PDF document text
    • http://mefijunov.pbworks.com/f/53181496414.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/cb98a67e-40cc-42e6-8dba-2575958f9a4b/zetuvas.pdfIn PDF document text
    • http://neruwuk.pbworks.com/f/inorder_preorder_postorder_traversal_examples.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/69c6d5ba-cfab-49d2-8b9d-803e68698bb3/percy_jackson_and_the_lightning_thief_book_chapter_5_summary.pdfIn PDF document text
    • http://lugozamuxika.pbworks.com/w/file/fetch/144416682/7512241316.pdfIn PDF document text
    • http://zuvevetub.pbworks.com/w/file/fetch/144421668/zitejedo.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/4000b479-268f-4931-b329-0e569edb680b/mupoposa.pdfIn PDF document text
    • http://lekuzax.pbworks.com/f/manual_bblico_de_guerra_espiritual.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/4d7adc71-1eaf-4bcf-ace8-3ddca7cd99d5/fukirowidugidupifeno.pdfIn PDF document text
    • http://poxanoralanu.pbworks.com/w/file/fetch/144423051/how_to_wash_my_milwaukee_heated_hoodie.pdfIn PDF document text
    • http://visetululiv.pbworks.com/w/file/fetch/144422331/can_a_washing_machine_timer_be_repaired.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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d034.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD034 5536 bytes
SHA-256: 42d279d9020130cfec615434b684b0341fb969878f716ce5260ad64d30f9feee
font_01_sfnt_off0000e2f7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE2F7 10640 bytes
SHA-256: a250677af7c92169e47d103f7efae0be735d041308a86518a624145c76232795

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