Malicious PDF — malware analysis report

Static analysis result for SHA-256 81bf8f311c57abe7…

MALICIOUS

PDF

75.7 KB Created: 2021-06-01 12:35:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-23
MD5: ef31d07cab272b85dd82471a643feaf7 SHA-1: d5e42f2a9d0e2a1a2ea2f7c71b0de8a44b219af9 SHA-256: 81bf8f311c57abe7d3096faf5ff8de61ce3209cce1d5ea654161a57d5b71bbf8
126 Risk Score

Malware Insights

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

The PDF file contains numerous embedded URLs, with a significant heuristic firing indicating it acts as a link farm on disposable hosting. One prominent URL, 'https://irlanc.ru/pbw?utm_term=black+swan+green+quotes+page+numbers', is flagged as external and suspicious. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware delivery, aligning with the Spearphishing Attachment technique.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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://irlanc.ru/pbw?utm_term=black+swan+green+quotes+page+numbers PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4480732/normal_6049b961d3a05.pdfIn PDF document text
    • https://static.s123-cdn-static-d.com/uploads/4374953/normal_60b19c17eada5.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4413587/normal_605f5c94163d8.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://funinupun.pbworks.com/w/file/fetch/144418524/nudexumu.pdfIn PDF document text
    • http://kokoxudalux.pbworks.com/w/file/fetch/144427449/how_to_make_gelatin_sheets_from_powder.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/f05c6ebf-d95b-40a1-8fef-f4e78e5db3ba/class_11_accountancy_book_ts_grewal.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/f429a9b8-d835-4598-a35b-4ef11b139927/cultural_psychology_heine_3rd_edition_citation.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/d898cec8-cc47-4e9d-98f1-8825b53977a0/nufetoxugenozibenukeb.pdfIn PDF document text
    • http://niwomif.pbworks.com/w/file/fetch/144424515/8937322884.pdfIn PDF document text
    • http://noxixap.pbworks.com/f/jisiwubutaxaziga.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/a64aa714-062f-444c-b9bc-780d1278713f/when_you_make_mistakes_quotes.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/2dfe3304-71e5-43f2-b30c-275720fea551/is_lithium_nitride_ionic_or_covalent.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/6f8ba42d-b13d-4fc2-a046-75aec2af92e4/pioneer_sph-da120_firmware_update.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/ffda61ed-06f7-4081-b47b-c1f078944d2b/88056734523.pdfIn PDF document text
    • http://garifukedako.pbworks.com/f/ntn_flange_bearing_catalogue.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/e236b203-e2fe-41d0-af6e-8736a099a2c8/is_china_a_constitutional_monarchy.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/c45f7a0e-9785-4e13-9f4a-c3040ea13550/tijuxodopaxiw.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/c83e9604-0385-462c-87c4-143c5eb0efec/neraxirilidakinifupofo.pdfIn PDF document text
    • http://siwuromo.pbworks.com/w/file/fetch/144425118/krispy_kreme_donut_holes_nutrition_information.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/82dfb4c2-2160-4142-a6dc-d04d0ca8d4c8/what_oil_can_replace_castor_oil.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_off0000e686.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE686 5724 bytes
SHA-256: 204682c1af63d7beb45212e93ec4222dfabba765817e0efab6af29bb50d284b2
font_01_sfnt_off0000f9fd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9FD 11136 bytes
SHA-256: 4216b5827c684a38148fa6d04fe3cede4ae6e81d1827337410fc5d8b9c6cf9fd

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