Malicious PDF — malware analysis report

Static analysis result for SHA-256 cb31523b1c72efaa…

MALICIOUS

PDF

83.1 KB Created: 2021-03-18 21:04:56 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-16
MD5: 8b07fa5de5c84f329c865935226d6fcb SHA-1: e8a827da0eebd9d2784b2f23608efad3f9ade332 SHA-256: cb31523b1c72efaaab2b32a74ea7671e7a783c7d08993f16e1e520b0d85bfe4b
186 Risk Score

Malware Insights

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

The PDF file was identified as malicious by ClamAV and an ML classifier, exhibiting characteristics of a link farm with numerous external URLs. The primary URL, 'https://maypoin.ru/123?utm_term=adding+decimals+with+models+worksheets', is suspicious and likely leads to a phishing or malware distribution site. The document's structure and the presence of many links suggest an attempt to lure users to external resources, aligning with spearphishing tactics.

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
  • 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.
  • 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://maypoin.ru/123?utm_term=adding+decimals+with+models+worksheets PDF link annotation
    • https://lapaluletegole.weebly.com/uploads/1/3/4/6/134679291/7621114.pdfIn PDF document text
    • https://foxuginatumusex.weebly.com/uploads/1/3/0/7/130775376/5587456.pdfIn PDF document text
    • http://maretexojud.66ghz.com/tenukeluwonopujo.pdfIn PDF document text
    • https://gifedoku.weebly.com/uploads/1/3/4/2/134234788/9669177.pdfIn PDF document text
    • http://requiremcgood.com/batman_arkham_asylum_game_for_pc4k6bh.pdfIn PDF document text
    • http://dwatches.site/597651759590xjkh.pdfIn PDF document text
    • https://cdn.sqhk.co/xafogatok/jZtNymQ/negivoxasukimatijok.pdfIn PDF document text
    • https://cdn.sqhk.co/baluwofuk/HDTzijJ/vokisi.pdfIn PDF document text
    • http://difuwikikum.iblogger.org/company_logo_design_free_template.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://828c6a01-da61-4814-986a-f72e64f4f334.filesusr.com/ugd/cdfdba_1e5c1de7f62344b7ac373a2798bfe86d.pdf?index=trueIn PDF document text
    • https://4ad55601-b8ab-4ae0-bc0e-e90069072326.filesusr.com/ugd/3aca14_3e61a7f7b87645e79d201969bdd9ec1f.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/zedilegol/manezetiw.pdfIn PDF document text
    • https://s3.amazonaws.com/jotizifime/elementary_linear_algebra_howard_anton_11th_edition_solution_manual.pdfIn PDF document text
    • https://s3.amazonaws.com/rekawexuretowo/56399490093.pdfIn PDF document text
    • https://5a4e7950-e122-4b3c-9cf7-894e7f5b1216.filesusr.com/ugd/76aeb6_bfd3f5c82ae740ba88dcfcbbbd9cae70.pdf?index=trueIn 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_off00010669.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10669 5496 bytes
SHA-256: 4b83fb71a42731c9afd0f1053a67a11aa804a909b8ca7824797f13a235abcc05
font_01_sfnt_off000118fc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x118FC 11252 bytes
SHA-256: d7e8cc6bbe042a9e00a36908b478027ab3fcf044cec11eea132f1c7509dd73ed

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