Malicious PDF — malware analysis report

Static analysis result for SHA-256 21e261baf52531c7…

MALICIOUS

PDF

85.6 KB Created: 2021-06-07 12:05:35 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-23
MD5: c84161b123a95727a04521cc4e6082ae SHA-1: 8b9bf92d59b6d4cd3bd744156bad0ac12c724538 SHA-256: 21e261baf52531c7c6d692cec8034ed0f53e4adb78d2eece3b0af86405c27b3c
186 Risk Score

Malware Insights

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

This PDF document was flagged as malicious by ClamAV and an ML classifier. The file embeds a large number of external links characteristic of an SEO link farm. Specific URLs and indicators for this sample are listed in the indicators section.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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
  • 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.
  • 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://krisoc.ru/pbw?utm_term=how+to+create+a+product+structure+tree+in+excel PDF link annotation
    • https://tafibukazun.weebly.com/uploads/1/3/5/4/135400045/231691.pdfIn PDF document text
    • https://mofasabopileb.weebly.com/uploads/1/3/4/1/134109330/21d0eb0e399.pdfIn PDF document text
    • https://xavixevoke.weebly.com/uploads/1/3/4/5/134590279/86533.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4408187/normal_604420af00027.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4410433/normal_606e85759a68b.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4467007/normal_5fd34364eeaf9.pdfIn PDF document text
    • https://zopiwaseka.weebly.com/uploads/1/3/0/9/130969839/menerimulapap-xezapadu-zulubowaziw.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4489050/normal_603a22a6d9747.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4371265/normal_5fca85d928701.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4383334/normal_60390a7c850b0.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4459937/normal_601d53208d399.pdfIn PDF document text
    • https://jekaximavu.weebly.com/uploads/1/3/4/7/134731662/bumimodamoduw-marupajur-vemise-zevitadajoletum.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://vafobotigef.pbworks.com/w/file/fetch/144499497/why_students_should_wear_uniforms.pdfIn PDF document text
    • http://sodopateduke.pbworks.com/w/file/fetch/144626973/10177791259.pdfIn PDF document text
    • http://wusagem.pbworks.com/f/principles_of_microeconomics_8th_edition_online_textbook.pdfIn PDF document text
    • http://denipugo.pbworks.com/w/file/fetch/144722781/25342093059.pdfIn PDF document text
    • http://pokuwatosat.pbworks.com/f/spy_the_lie_romana.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/c2eaed5a-5740-46ba-a20a-821f7a54edae/lord_of_the_flies_chapter_5_study_questions_and_answers.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/81bd99e0-d79b-4568-b717-5af3f868cc95/xepamudeguziponevimebabe.pdfIn PDF document text
    • http://fozujedax.pbworks.com/w/file/fetch/144683619/the_chronicles_of_narnia_prince_caspian_book_review.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000107aa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x107AA 5188 bytes
SHA-256: 9b1bd90eb23e066a4f0e27ecd6a7a98beda8850dc26bc192451c0948541f30f0
font_01_sfnt_off00011968.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11968 1800 bytes
SHA-256: a36eee06fef6ce219692c4ec918276ac99413e4fd1e3666e4031624f9289d620
font_02_sfnt_off000121f5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x121F5 11292 bytes
SHA-256: ab4f2cc8e392b84e5c2222969cdbf5c91da1127b1d89bfd9e4f8b3a950077c7a