Malicious PDF — malware analysis report

Static analysis result for SHA-256 3b379873a0dcba94…

MALICIOUS

PDF

86.9 KB Created: 2021-04-09 02:45:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 532849e8b4e57343d5410b6b0cf8e7c6 SHA-1: 974d8aaf1fe429003e14491873367227bed58401 SHA-256: 3b379873a0dcba94566f1ee53f4b25efadbf734448ec1490e73bfbfd301d50a9
156 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many pointing to other PDF files, which is indicative of a link farm or SEO manipulation tactic. The primary malicious URL identified is https://jacksth.ru/strik. While no scripts were explicitly extracted, the PDF structure and the presence of numerous external links suggest an attempt to redirect users to potentially malicious or deceptive content. The ML classifier and ClamAV detection strongly support a malicious classification.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • 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-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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=metodologia+de+la+investigacion+sampieri+resumen+pdf
    • https://cdn-cms.f-static.net/uploads/4477162/normal_6022c2cc2f8d1.pdf
    • https://kadeborejegan.weebly.com/uploads/1/3/2/7/132740978/tirenosali_tusarupele_firejuxox.pdf
    • https://static.s123-cdn-static.com/uploads/4483842/normal_6004143358f6b.pdf
    • https://cdn-cms.f-static.net/uploads/4382406/normal_602436e86e919.pdf
    • https://static.s123-cdn-static.com/uploads/4474457/normal_5ff6797996834.pdf
    • https://zokofefedepop.weebly.com/uploads/1/3/1/4/131437243/e38e90079efa.pdf
    • https://cdn-cms.f-static.net/uploads/4375358/normal_6053a6b857bbe.pdf
    • https://cdn-cms.f-static.net/uploads/4495400/normal_602a51f9408e3.pdf
    • https://lozuninusagutog.weebly.com/uploads/1/3/5/3/135309735/0425d1b93.pdf
    • https://cdn-cms.f-static.net/uploads/4500450/normal_60477394247a2.pdf
    • https://risebezisenozo.weebly.com/uploads/1/3/4/3/134375164/5049097.pdf
    • https://cdn-cms.f-static.net/uploads/4457008/normal_6066bff45b9c9.pdf
    • https://static.s123-cdn-static.com/uploads/4383916/normal_5ffcd7d4aa114.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://uploads.strikinglycdn.com/files/256463a8-e83b-4ff1-9c9b-8f810019087a/jojuvi.pdf
    • https://s3.amazonaws.com/ninasivol/kikajiwupekimuk.pdf
    • https://uploads.strikinglycdn.com/files/b8273516-826c-481f-a085-7be45c229d1f/ziviwokozuva.pdf
    • https://uploads.strikinglycdn.com/files/c9a9db3f-409b-48bb-a45f-d4dca75ca2c2/bufigenudopopate.pdf
    • https://s3.amazonaws.com/dogazisuze/put_the_words_in_alphabetical_order_exercises.pdf
    • https://uploads.strikinglycdn.com/files/067d8f49-5162-4c60-bf02-432ac3154d62/the_urban_farmer_curtis_stone.pdf
    • https://s3.amazonaws.com/vokeri/what_reading_level_is_junie_b_jones_has_a_monster_under_her_bed.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_off00011202.bin
b3900080726255f70e97b8a6858a11bef6f30d4c75f46aaaf8efd49190d66393		 pdf-font-stream PDF embedded font (sfnt) at offset 0x11202 5540 bytes
font_01_sfnt_off000124db.bin
a510e9b371931b1beddb59868746cd51bbe26547eab590054c4be8f78d1debd7		 pdf-font-stream PDF embedded font (sfnt) at offset 0x124DB 12304 bytes

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