Malicious PDF — malware analysis report

Static analysis result for SHA-256 b857a235b5c589fe…

MALICIOUS

PDF

103.6 KB Created: 2021-02-16 03:47:05 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-22
MD5: 7c86d73064b5e2f59fdc54046cdacefa SHA-1: 50bd83c7fe705b74ac8f98cbe0fa84443ee2209a SHA-256: b857a235b5c589fea06e24de4a54c5a350214d3f9e66ea0a92eefd8882229b71
156 Risk Score

Malware Insights

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

The PDF file contains a significant number of embedded external links, as indicated by the 'PDF_SEO_LINK_FARM' heuristic. The primary malicious URLs identified are 'https://baarspo.ru/strik' and 'http://remeik.ru/mejinigesuxekon4801.pdf'. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware distribution through these links.

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 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.
  • 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://baarspo.ru/strik?utm_term=database+management+systems+3ed+r.+ramakrishnan+and+j.+gehrke PDF link annotation
    • http://remeik.ru/mejinigesuxekon4801.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4501770/normal_5fd22f3689fbb.pdfIn PDF document text
    • http://wide-do.top/barcode_font_excelydh9x.pdfIn PDF document text
    • https://cdn.sqhk.co/zuxeromewime/kL2Hhb7/first_aid_certification_oregon.pdfIn PDF document text
    • https://megularebenava.weebly.com/uploads/1/3/1/1/131164421/tetiwukadilapux-welejarifodal.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4409421/normal_5fd173d975c7c.pdfIn PDF document text
    • http://ionatr.space/67327777303b6tay.pdfIn PDF document text
    • https://cdn.sqhk.co/lilaxikixo/ggiiIhf/sezefoxowimu.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4369505/normal_5fd6dfb7256f0.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4380223/normal_60248847222af.pdfIn PDF document text
    • https://rizebilawi.weebly.com/uploads/1/3/0/8/130814716/rijabubor.pdfIn PDF document text
    • https://mavuzoxawajike.weebly.com/uploads/1/3/0/9/130969593/fuvudemeximaduj.pdfIn PDF document text
    • http://tourist.fish/core_econ_exercise_answersgsn77.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/bibejovixapis/clip_india_2018_song.pdfIn PDF document text
    • https://s3.amazonaws.com/nezanurugega/social_skills_worksheets_for_adults.pdfIn PDF document text
    • https://s3.amazonaws.com/tobovunoberiki/segofubovaretelaluxivetan.pdfIn PDF document text
    • https://s3.amazonaws.com/wujanozo/evaluating_functions_matching_worksheet_answer_key.pdfIn PDF document text
    • https://s3.amazonaws.com/likerajatob/checklist_template_excel_free.pdfIn PDF document text
    • https://s3.amazonaws.com/gawabog/engineering_weight_calculator_free.pdfIn PDF document text
    • https://s3.amazonaws.com/zowejunef/57342151280.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_off000154b4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x154B4 5784 bytes
SHA-256: 2438a7df446ca5cabb5d5516f99fa5177a4fcd850de7b72a49d421b92d237edd
font_01_sfnt_off00016852.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x16852 12672 bytes
SHA-256: da3993bedaeaa182d78d3ced97c9b72b78f47fe5cc1ca1ba9ec615477a263666

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