Malicious PDF — malware analysis report

Static analysis result for SHA-256 931176aa9c0a04bb…

MALICIOUS

PDF

81.3 KB Created: 2021-02-20 01:11:37 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-07
MD5: daa7d4880a1dfa6198bd60ad07b1b9f9 SHA-1: 5b16db89132ee17bcc8518bc96b72d184dd5cd4d SHA-256: 931176aa9c0a04bb2f7bd4fab255b9f7ae09e17af71a1fb76e5565faaf8c8705
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

This PDF file was flagged as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains a large number of external links, many hosted on disposable domains, suggesting a link farm or SEO manipulation tactic. One URL, 'https://baarspo.ru/strik?utm_term=best+textbooks+for+medical+students', appears to be a redirector. The document body is heavily obfuscated and contains metadata suggesting it was generated by wkhtmltopdf, which can be abused to create malicious PDFs.

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://baarspo.ru/strik?utm_term=best+textbooks+for+medical+students PDF link annotation
    • https://relitemora.weebly.com/uploads/1/3/4/3/134352419/duxupojanunipuwoso.pdfIn PDF document text
    • https://lofefogurabu.weebly.com/uploads/1/3/1/1/131164054/fafunedikimoratoluno.pdfIn PDF document text
    • https://jedidaril.weebly.com/uploads/1/3/4/6/134687024/gupiros.pdfIn PDF document text
    • https://viwosakizipisot.weebly.com/uploads/1/3/5/3/135321869/a65bf3e37a.pdfIn PDF document text
    • https://wopatozobaw.weebly.com/uploads/1/3/2/6/132682171/bcf69a5ca1.pdfIn PDF document text
    • http://bigwin-1xbet.fun/vlookup_for_multiple_sheets80dgs.pdfIn PDF document text
    • https://rasizuxuner.weebly.com/uploads/1/3/1/3/131378923/cdada88b.pdfIn PDF document text
    • http://presente-top.store/magic_chef_4.5_cu._ft._mini_fridge_with_true_freezer_in_stainless_lookyfaek.pdfIn PDF document text
    • https://kalepadakib.weebly.com/uploads/1/3/1/6/131637037/xavurefo.pdfIn PDF document text
    • http://lifeshop.pro/sample_application_letter_for_accounting_positionkhsxk.pdfIn PDF document text
    • http://arenaprobet.com/nitumikogexofaso4nc2f.pdfIn PDF document text
    • https://wodanosivowifig.weebly.com/uploads/1/3/4/5/134593279/vezivowamabipa.pdfIn PDF document text
    • https://wejerimaz.weebly.com/uploads/1/3/4/6/134648800/3a730d653e6.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://sirowozikuko.epizy.com/vba_activesheet._pastespecial_xlvalues.pdfIn PDF document text
    • http://piwalalif.rf.gd/42490225727.pdfIn PDF document text
    • http://verafewema.rf.gd/poesias_inditas_fernando_pessoa.pdfIn PDF document text
    • https://s3.amazonaws.com/muvazi/wrong_turn_4_movie_free.pdfIn PDF document text
    • https://s3.amazonaws.com/nosepevozux/garmin_gps_app_android.pdfIn PDF document text
    • https://s3.amazonaws.com/gelawiweza/7744568138.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_off0000fff4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFFF4 5488 bytes
SHA-256: 5c9f5b50289c2e3159139fdf1bd582c049b558e515c6554d7dd66ca95048ec68
font_01_sfnt_off0001128f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1128F 10856 bytes
SHA-256: e4ec0672dc09e9095245ecff0b474ba3e00816c470c56facb1cda0f1ddb22f81

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