Malicious PDF — malware analysis report

Static analysis result for SHA-256 a51067cd2cb4c4e8…

MALICIOUS

PDF

74.7 KB Created: 2021-06-08 23:04:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-13
MD5: a4508ff331d06f2762f22a93538bfb5c SHA-1: 686ebb8b0a8d09ef9e743fde79ee244a9b56a1c1 SHA-256: a51067cd2cb4c4e847a7c9687f145df391635074801f2029865f522362a3fab3
126 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

The PDF contains numerous external links, with one prominent URL pointing to a suspicious domain that is likely part of a phishing or malware distribution campaign. The ML classifier and ClamAV detection strongly indicate malicious intent. Although no scripts were explicitly extracted, the PDF structure and link farm heuristic suggest it's designed to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://jacksth.ru/123?utm_term=honeydew+class+8+book+question+answer PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4479254/normal_60236afd618f9.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4373301/normal_5fca6b991ea18.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4465267/normal_601b6c756bc90.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4416321/normal_604793a0e79b8.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4454821/normal_6015b6265985e.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://xutipofapu.pbworks.com/w/file/fetch/144740301/why_use_non_probability_sampling.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/542ac6a6-1665-4319-9a73-9b9318f9702b/34881248048.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/84676f75-9f0c-4a43-a57d-6c583c02c774/2000_polaris_xplorer_400_specs.pdfIn PDF document text
    • http://xuladejuzor.pbworks.com/f/how_much_is_adobe_acrobat_for_mac.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/ba7c47c2-c668-40ad-9f52-8afed77e8634/27613203945.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/ac3aa8e9-c94c-40fd-850e-cd3414c7496c/87850443519.pdfIn PDF document text
    • http://paditoxef.pbworks.com/w/file/fetch/144563058/fundamentals_of_thermodynamics.pdfIn PDF document text
    • http://jujupaw.pbworks.com/w/file/fetch/144631341/almanca_a2_kelimeler.pdfIn PDF document text
    • http://zikasamu.pbworks.com/f/how_to_repair_whirlpool_washing_machine_timer.pdfIn PDF document text
    • http://fufitiruw.pbworks.com/f/vocabulary_packets_greek_and_latin_roots_unit_1_answer_key.pdfIn PDF document text
    • http://dibesusajob.pbworks.com/w/file/fetch/144460458/jeritabeniz.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/a8701a45-4dbe-4bd5-ad5a-ec4aa8b60b4a/best_bluetooth_keyboard_for_samsung_tablet.pdfIn PDF document text
    • http://rajejor.pbworks.com/f/how_to_recover_from_tooth_decay_naturally.pdfIn PDF document text
    • http://tisowowuduwe.pbworks.com/f/sample_of_letter_of_intent_for_scholarship.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_off0000e3af.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE3AF 5612 bytes
SHA-256: bffbc689385558f2d339699f23caff13b75cdd80a1a82b9cf1e3ad2712d93d54
font_01_sfnt_off0000f6e4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6E4 10928 bytes
SHA-256: 5947fc532fd493c9ab9d5793334031b00eb7ebc3d563576eac974e4eee365f11

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