Malicious PDF — malware analysis report

Static analysis result for SHA-256 87a84cbb91641d8b…

MALICIOUS

PDF

75.0 KB Created: 2021-02-21 22:53:40 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-12
MD5: 6ba4a0e66dc63595a362556a6da20001 SHA-1: 63f474ee4a3defb983b84d0e83f88f3c75a9cc15 SHA-256: 87a84cbb91641d8b49c45942e45981c416b84afe1eec6b381620d101727a8e34
126 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which are hosted on disposable domains and appear to be part of a link farm. The primary malicious URL, https://bologen.ru/strik?utm_term=what+are+the+main+rivers+in+south+africa, is disguised as a search query, likely to trick users into clicking it. The ML classifier and ClamAV detection strongly indicate malicious intent, classifying it as phishing malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://bologen.ru/strik?utm_term=what+are+the+main+rivers+in+south+africa PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4388157/normal_5fd99aa7ce4de.pdfIn PDF document text
    • http://dofukatejipoz.66ghz.com/13187692595.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4378425/normal_60109317bda88.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4454184/normal_5fcf13af975e8.pdfIn PDF document text
    • https://cdn.sqhk.co/venitalobeni/jiwichj/french_style_nails_pinterest.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4421639/normal_6014049a916e3.pdfIn PDF document text
    • http://goduvide.22web.org/pathology_lab_report_software_free.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4491157/normal_601ffd558a225.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4470389/normal_6017bbca290ab.pdfIn PDF document text
    • https://cdn.sqhk.co/rufopunuk/gAGgcjj/countries_of_the_world_flags_quiz.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://vijesir.rf.gd/bookman_italic_font_free.pdfIn PDF document text
    • https://s3.amazonaws.com/polexebuj/acr_guidelines_for_screening_mammograms.pdfIn PDF document text
    • https://s3.amazonaws.com/tufitijinexu/gangotri_audio_songs_telugu_lo_ing.pdfIn PDF document text
    • https://s3.amazonaws.com/kotodur/18025667970.pdfIn PDF document text
    • http://menaronutex.epizy.com/can_i_pay_my_credit_one_bill_over_the_phone.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_off0000e6e1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE6E1 5164 bytes
SHA-256: a4188cae2b7fb168f0368eaa9462b1a47254fe0f2ceb77af250832ee94e58420
font_01_sfnt_off0000f855.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF855 10968 bytes
SHA-256: 3b718e4015e61f509870bee636f71c4ac6f30ff9302743b4cbf7d72a73395b50

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