Malicious PDF — malware analysis report

Static analysis result for SHA-256 3bfb39c5b50951a3…

MALICIOUS

PDF

83.2 KB Created: 2021-04-24 04:25:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 3a0c405c792e2c62d561742a71825449 SHA-1: 96a6447fb56a07673943c356192ebe14908e627d SHA-256: 3bfb39c5b50951a3ff64345b6ad7690cee3345b589f8baa67c34ab81d54fe739
186 Risk Score

Malware Insights

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

This PDF file is classified as malicious by ML and ClamAV, indicating a high probability of malicious intent. It functions as a link farm, embedding numerous external URLs, many of which point to disposable hosting services. The primary purpose appears to be directing users to potentially harmful content or phishing sites under the guise of educational worksheets.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 6

  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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/strik?utm_term=grade+3+maths+worksheets+pdf+south+africa
    • https://tapogizixe.weebly.com/uploads/1/3/4/8/134897788/cc8c49f3.pdf
    • https://gawinesiti.weebly.com/uploads/1/3/5/3/135383431/pigakajotogi-kuxonoj-zumonej.pdf
    • https://sufusazowuk.weebly.com/uploads/1/3/4/3/134311692/8530107.pdf
    • https://cdn-cms.f-static.net/uploads/4366020/normal_6049297f1939a.pdf
    • https://rewoseluvepe.weebly.com/uploads/1/3/4/6/134683186/490169.pdf
    • https://jupavovol.weebly.com/uploads/1/3/4/3/134314217/vefalovuropodaxon.pdf
    • https://tejojapifofomo.weebly.com/uploads/1/3/4/3/134339563/wewunekosemaxanexig.pdf
    • https://cdn-cms.f-static.net/uploads/4388271/normal_6025a42f88b68.pdf
    • https://cdn-cms.f-static.net/uploads/4475380/normal_605b6e37e6436.pdf
    • https://cdn-cms.f-static.net/uploads/4402948/normal_602fa43b9ee88.pdf
    • https://wosabawa.weebly.com/uploads/1/3/5/3/135390578/08fa4e26e32c6.pdf
    • https://cdn-cms.f-static.net/uploads/4445119/normal_606e1af9a01f5.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://018ae6bf-5b6e-4bf7-bb5f-89503284f855.filesusr.com/ugd/b7931c_1855f00c01f54790b9e7f64546b11f50.pdf?index=true
    • https://s3.amazonaws.com/temujonuwu/vuwajudekigev.pdf
    • https://uploads.strikinglycdn.com/files/30dc054a-7260-436a-9713-48ec7e4eee83/water_resources_engineering_notes_download.pdf
    • https://s3.amazonaws.com/mujesogi/eragon_book_5.pdf
    • https://s3.amazonaws.com/fibesezati/que_son_los_tipos_de_organizadores_graficos.pdf
    • https://uploads.strikinglycdn.com/files/3d377556-7eac-4132-8a02-c0dabb906ac0/98_long_haul_covid_symptoms.pdf
    • https://uploads.strikinglycdn.com/files/b404498f-5ab8-4c33-989d-a84db021080f/braun_silk_epil_9_price_in_uae.pdf
    • https://fac7854b-22c3-40b9-bef9-ee94a55a010d.filesusr.com/ugd/fba82c_36f3c0b8834347dc85ebe9b7c6c45502.pdf?index=true
    • https://s3.amazonaws.com/timeziso/professional_bureaucracy_form_of_structure_examples.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0001032a.bin
1481cb8c06709ddfcd676a914a3a55d4d71e053763ebc70213e311e4e7548bc7		 pdf-font-stream PDF embedded font (sfnt) at offset 0x1032A 5716 bytes
font_01_sfnt_off00011692.bin
82e457849e31456e20f39e9147c87bc4b9b1e8d55efecd1c24316b74e890e6c3		 pdf-font-stream PDF embedded font (sfnt) at offset 0x11692 11976 bytes

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