Malicious PDF — malware analysis report

Static analysis result for SHA-256 f8157c9d926b768d…

MALICIOUS

PDF

79.3 KB Created: 2021-03-15 03:14:28 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-25
MD5: d20c63664dded0e9570851d7d7ce6799 SHA-1: 496277ee3546e8c46fc07e28c3f8adb94ee3d40b SHA-256: f8157c9d926b768d25d44eff580a79d89a56845ae7aa82f566513158d970abca
186 Risk Score

Malware Insights

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

The PDF file contains a large number of external links, many of which point to disposable hosting, suggesting a link farm or phishing operation. The ML classifier and ClamAV detection strongly indicate maliciousness. The embedded URL `https://pelibifir.ru/123?utm_term=aged+care+guidelines+2018` is likely the primary lure, disguised as 'aged care guidelines'. No scripts were extracted, but the PDF structure itself is indicative of malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 6

  • 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 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://pelibifir.ru/123?utm_term=aged+care+guidelines+2018 PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4480884/normal_5fd1ee1cdb22e.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4531523/normal_60479eb168ea3.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4461498/normal_604e9cdc58c4a.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4379959/normal_5fee42ff9f118.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/wegemebufojafak/1796848165.pdfIn PDF document text
    • https://e055bcc9-c4f1-4c6c-8dcb-0912bf54750f.filesusr.com/ugd/b4a829_3247b58f693a4b349ee046851e2b3914.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/pegebunov/larefudinolozezigovifotu.pdfIn PDF document text
    • https://1cd0d4d5-11d4-440c-a307-81f73801f601.filesusr.com/ugd/f0e51d_593f3d3cbe22458fa108780594b60098.pdf?index=trueIn PDF document text
    • https://d6aab468-caab-4d9e-910f-d3bf64ae4104.filesusr.com/ugd/5438e3_fe1b909e7d1f44348f4ea25de778e74a.pdf?index=trueIn PDF document text
    • https://cef8af8d-7071-4339-ac50-fc417d371010.filesusr.com/ugd/a89196_6d42e007d15f419791993ddf8b347131.pdf?index=trueIn PDF document text
    • https://7a9095e9-4ba3-4ff7-9406-a75d0382ce8a.filesusr.com/ugd/db93e9_83bc9ad1939443a7b6c5c3b44817a327.pdf?index=trueIn PDF document text
    • https://e50eee24-2d95-422d-8083-6f618d95927b.filesusr.com/ugd/594ae5_31068f881d8749db9600107dbce5f4a1.pdf?index=trueIn PDF document text
    • https://b56e6f12-3f4b-4b75-bc29-9585eb3fba71.filesusr.com/ugd/73f0dd_84318a4e5b51407488ff8d5db5452e75.pdf?index=trueIn PDF document text
    • https://db6d201d-bdff-4648-9982-d9cfaac7639e.filesusr.com/ugd/98857b_6f71a112871842f597a056927868f06c.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/zuniverijesud/diabetes_driving_guidelines_australia.pdfIn PDF document text
    • https://3d3b31fc-6152-41c7-b1d4-a4af3afcce63.filesusr.com/ugd/3f8d85_00e30617c5fa478ca10ce901c5f887cf.pdf?index=trueIn PDF document text
    • https://53ebb62d-ddaf-432f-8dc3-1f4746653467.filesusr.com/ugd/bbd3cf_4dfb0063e3f943abb8d235a80217da34.pdf?index=trueIn PDF document text
    • https://9526c93a-d340-4dca-b5fd-2864ff0888c4.filesusr.com/ugd/4c3d6a_265fdf2a20b74d6b9cdb31e28c0b7fb0.pdf?index=trueIn PDF document text
    • https://45b0b119-5f8c-43e7-b437-4e12d17c1c81.filesusr.com/ugd/3826db_6d658c26d2384014808e37ee8d2a39f1.pdf?index=trueIn PDF document text
    • https://91313464-3f42-441e-b0e8-b27065d471ad.filesusr.com/ugd/ee9d3f_cad052ce4d834f789bafc0743cc2aaff.pdf?index=trueIn PDF document text
    • https://aa700e4b-9450-4a85-8b7e-8c92ffe47626.filesusr.com/ugd/de972d_a0a49d4a5c0143c7a2ca663fe44fc9b1.pdf?index=trueIn 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_off0000f97c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF97C 5616 bytes
SHA-256: 3786de9665c471029f6232af0bdc9edf303393f66f219c2f868fcc284eb725a2
font_01_sfnt_off00010ca1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10CA1 10380 bytes
SHA-256: c30d902ddfaed236a8a88c8b9771926c65833451e0940b0c9d14759dc6bcae09

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