Malicious PDF — malware analysis report

Static analysis result for SHA-256 827556f4d5c445b6…

MALICIOUS

PDF

83.8 KB Created: 2021-05-03 20:52:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: f6cdbd162fc0e2fb1d329b5a78d46b89 SHA-1: 7ad96d8b83ae3af6ef96b8022dce62a8ab3bb9a7 SHA-256: 827556f4d5c445b60ffd943eb81e1c132b49f161e33004637b6b841852872ce4
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 pointing to disposable domains, suggesting a link farm or SEO spam operation. The ML classifier and ClamAV detection strongly indicate malicious intent, specifically phishing. While no scripts were directly extracted, the PDF structure and heuristics point towards techniques used to redirect users to malicious sites, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 6

  • 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-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://kuzutuzo.ru/strik?utm_term=types+of+bonding+practice+worksheet+answers
    • http://mybiol.site/kalilepexabivalovieyk5m.pdf
    • http://homebig.space/fezozaxatulaweokxbt.pdf
    • http://citruss.space/bozuxvpv9h.pdf
    • https://verevivomilob.weebly.com/uploads/1/3/0/7/130738769/c9aed87.pdf
    • https://cdn-cms.f-static.net/uploads/4450721/normal_606171c565392.pdf
    • https://cdn-cms.f-static.net/uploads/4451019/normal_6009d20a41e9d.pdf
    • http://mafejaruvoje.sportsontheweb.net/language_acquisition_and_language_learning.pdf
    • https://mijevofere.weebly.com/uploads/1/3/1/6/131606011/pegoruka-pazokodogedupa-xokokemubiwew-xosivezivi.pdf
    • https://cdn-cms.f-static.net/uploads/4489251/normal_6065e9c2458fd.pdf
    • http://tejowigasinafu.getenjoyment.net/como_convertir_un_archivo_a_word_editable_gratis.pdf
    • http://bosuxezaxad.mypressonline.com/speak_business_english_like_an_american_free_download.pdf
    • http://proba7.xyz/what_is_a_significant_difference_between_viral_pneumonia_and_bacterial_pneumoniab86oe.pdf
    • http://tanivikovome.sportsontheweb.net/beatriz_sarlo_borges.pdf
    • https://static.s123-cdn-static.com/uploads/4459028/normal_6004b20b536f0.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://s3.amazonaws.com/punagilelabon/nisanovasu.pdf
    • https://da9d63b4-fbfd-4f6f-88e7-06ac0d76355b.filesusr.com/ugd/ca300b_aa1266da5d184369841fa9d71f397b96.pdf?index=true
    • https://676a7a22-5bec-432e-92e0-9d4a0a27851c.filesusr.com/ugd/a1fb72_742f3e895cf34fbe83bf3a15b01e1e2d.pdf?index=true
    • https://a6047d18-b57f-4fdc-88fa-dea7715a8642.filesusr.com/ugd/189347_853b5cbeb5424a598f6a58430988f1fc.pdf?index=true
    • https://5613ab86-cfe5-4642-b9e1-29ab5e510d76.filesusr.com/ugd/79e000_8742d796957e496ab9691bf287c4291c.pdf?index=true
    • https://s3.amazonaws.com/rujabepifar/63462927567.pdf
    • https://s3.amazonaws.com/vojapu/30022234772.pdf
    • https://8c805f22-5240-4a8e-9b4d-8499607ff1fc.filesusr.com/ugd/76156b_e2d1d2b460184b3aa054e28fd654984e.pdf?index=true
    • 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_off00010647.bin
5fd29d50f517ef65e3760ca95284b35f08feaf2218b1116e0af286d4593c7a96		 pdf-font-stream PDF embedded font (sfnt) at offset 0x10647 5732 bytes
font_01_sfnt_off000119dd.bin
833d17a910a7077ff3e946af2aa5b8253ab5fc4d6a9a495885054d5eae6986e7		 pdf-font-stream PDF embedded font (sfnt) at offset 0x119DD 11692 bytes

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