Malicious PDF — malware analysis report

Static analysis result for SHA-256 40bcd219a16f95f2…

MALICIOUS

PDF

81.3 KB Created: 2021-02-09 03:41:22 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-22
MD5: 37ea0a753de9da7d2a9d841d4c0c79c4 SHA-1: 8d4a519b48a3e47ecfbef1de9b783d47d3851767 SHA-256: 40bcd219a16f95f204536b1e03fef805b472ceb451c112d667c0bc0daebbb08e
126 Risk Score

Malware Insights

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

This PDF file was flagged as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The document body, though partially corrupted, contains text suggesting it is a lure for 'maths limits questions and answers pdf'. It embeds multiple URLs, with one prominent URL pointing to 'jacksth.ru', which is likely part of a phishing or malware distribution scheme. The presence of external URIs and the link farm heuristic further support a malicious purpose.

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://jacksth.ru/123?utm_term=maths+limits+questions+and+answers+pdf PDF link annotation
    • https://cdn.sqhk.co/zozotetowa/lhghcCI/10301612114.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4476750/normal_601d531c42dd2.pdfIn PDF document text
    • https://cdn.sqhk.co/javeduner/Sdnjjjf/bubbu_my_virtual_pet_download_apk.pdfIn PDF document text
    • http://rankingcoach-seo.com/83576879011iweio.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4454672/normal_6019c0e21c4c1.pdfIn PDF document text
    • https://pigamudabuv.weebly.com/uploads/1/3/4/2/134235231/luvopenisapa_zezivoxiwo.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4374175/normal_5fcef47389547.pdfIn PDF document text
    • https://cdn.sqhk.co/dikulodut/EjhpDZZ/running_warehouse_coupon_codes_not_working.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4366993/normal_601669c3264c9.pdfIn PDF document text
    • https://verosogoteri.weebly.com/uploads/1/3/4/7/134738646/negefefufadapav_satawukirama_jawojexovisum.pdfIn PDF document text
    • https://befugusugub.weebly.com/uploads/1/3/2/6/132683140/zugaw-nafevirasekugas-tubetepitupile-defol.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/kuxuxemu/performance_appraisal_report_writing.pdfIn PDF document text
    • https://s3.amazonaws.com/jasipefulaxiduj/filokojatibazax.pdfIn PDF document text
    • https://s3.amazonaws.com/tawovojo/flight_radar_24_pro_apk_mod.pdfIn PDF document text
    • http://lenawevurokolup.epizy.com/cervical_cerclage_procedure.pdfIn PDF document text
    • http://bavidoripo.epizy.com/82057354583.pdfIn PDF document text
    • https://s3.amazonaws.com/fuvidokibet/10th_class_maths_book_rbse_2019.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_off0000ff81.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF81 5504 bytes
SHA-256: e339af3a86f767bcad272cb2c89793406a8796fb2067336d4f761b0ebf1ae54b
font_01_sfnt_off00011226.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11226 11580 bytes
SHA-256: 6f87d759a180a1dced7cd2d675d43f82a1d8a50f8d519b927a92f2a34fa16687

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