Malicious PDF — malware analysis report

Static analysis result for SHA-256 f2439a1465f8b8e6…

MALICIOUS

PDF

77.8 KB Created: 2021-05-09 16:11:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-03
MD5: c90397e2320133017275f5915a5f93ad SHA-1: 2c9659da3945a9fab94684321a034936c5ac148a SHA-256: f2439a1465f8b8e6e2caad807a0fe79aae0b5be281ea35458f2237c48be5bc21
244 Risk Score

Malware Insights

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

The PDF contains a large number of embedded links, many of which point to disposable hosting or are part of a link farm. One of the URLs, 'https://yafferge.ru/strik?utm_term=how+does+density+change+with+altitude', is flagged as a malicious redirector. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware distribution via these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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
  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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.
  • 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://yafferge.ru/strik?utm_term=how+does+density+change+with+altitude In PDF document text
    • http://xafesuvorolivig.scienceontheweb.net/lizoxutimo.pdfIn PDF document text
    • http://mamajan.space/basic_marketing_terms_and_definitions4yhoy.pdfIn PDF document text
    • http://funasowuto.getenjoyment.net/59583138957.pdfIn PDF document text
    • http://bopugafuwu.scienceontheweb.net/english_language_basic_knowledge_questions_and_answers.pdfIn PDF document text
    • http://bukipumil.mypressonline.com/12665274829.pdfIn PDF document text
    • http://bezprovodov.guru/bedrag_ex_btw_berekenen_formuleqfzep.pdfIn PDF document text
    • http://lebizifijafaxim.medianewsonline.com/bilezifun.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://77bac38d-831a-46d6-8f22-d7743fcadc58.filesusr.com/ugd/5b9a87_231f3a5e63f04984980752915b2dad63.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/lopadivupudexa/ahmadiyya_nazam_free.pdfIn PDF document text
    • https://82f7a8bd-e2a3-46ec-bdf8-dd4727f017fb.filesusr.com/ugd/a90de3_4af4fe174ce24f61becd076312c753d1.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/jazamerijekufol/alpha_omega_elite_car_seat_review.pdfIn PDF document text
    • https://3c2b787d-8465-4662-bdcc-bf736d584291.filesusr.com/ugd/8760e7_adfd9a86b6e449b7836ccc61a8e009f6.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/1f628cf3-9c27-49f9-9652-9d07eb1ba700/dalovekibuwomejojujitas.pdfIn PDF document text
    • https://0b21792c-a699-4cf4-8833-5910c6ad58af.filesusr.com/ugd/b0b521_67f570678bea41d19b5a03e30982db37.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/85adb615-5c99-4c75-89a0-dd4a6faae196/seluravuxitugufapibagesij.pdfIn PDF document text
    • https://3e1af3dc-cf37-4f58-935d-0a6065bc5ce9.filesusr.com/ugd/3ca236_4f3d6ce802064fa88659c65a72f942aa.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/84e41ca5-1979-4366-818e-d65c921260b3/how_many_molecules_are_contained_in_each_compound_a.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/82653d1c-0049-4fe3-ab2c-6c4ff9dea649/tipos_de_sistemas_del_cuerpo_humano.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_off0000f34a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF34A 5260 bytes
SHA-256: 7b99a27bf60d593bfc20214f5d386f506d8acc10ed218137a5809a2e6f05fb57
font_01_sfnt_off00010549.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10549 10620 bytes
SHA-256: 6eb0f3de2a47ea32daa8eecc195f178e857b2e12129f9f5f78b6cd47fcee5adb