Malicious PDF — malware analysis report

Static analysis result for SHA-256 f2fded4cb9a1fa18…

MALICIOUS

PDF

136.1 KB Created: 2021-07-02 10:48:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-25
MD5: 3e555c8f903aa960c3d71e09fe66a564 SHA-1: 5d8635bb213d07404477256123f7ce2c5a1ddb9c SHA-256: f2fded4cb9a1fa181053f8a068b0a48f5047e4b6856930d0beadc5f5719b0613
204 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, with heuristics indicating it functions as a fake CAPTCHA or human verification prompt. This suggests an attempt to lure the user into executing malicious content or commands. The document also contains numerous links to external sites, some hosted on compromised CMS platforms, which likely serve as download locations for secondary payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9933

Heuristics 8

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Fake CAPTCHA / human verification prompt high SE_FAKE_CAPTCHA
    Document displays a fake CAPTCHA or human-verification prompt — used to trick users into running commands or pressing keyboard shortcuts
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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.
  • Urgency / deadline lure low SE_URGENCY_LURE
    Document contains urgency or deadline language ('account will be terminated', 'action required within 24 hours', etc.) — useful context, but low-signal without other findings
  • 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://synerhu.ru/uplcv?utm_term=non+remarriage+certificate+format PDF link annotation
    • https://sjalikave.hu/pictures/file/83049759547.pdfIn PDF document text
    • http://transbur.ru/admin/ckfinder/userfiles/files/ruxibetifotilijawabixoj.pdfIn PDF document text
    • https://verandapattaya.com/userfiles/files/99371222223.pdfIn PDF document text
    • http://lbhodgereunion.com/clients/3/38/38e1f81cb1ac74d12d86c8ba87866b9f/File/14254256148.pdfIn PDF document text
    • http://aivieksteslaivas.lv/userfiles/file/novafepabarakegajagiva.pdfIn PDF document text
    • http://www.loockuniformes.com.br/home/wp-content/plugins/formcraft/file-upload/server/content/files/160b289ca1f92c---kokezuzijaregidofu.pdfIn PDF document text
    • https://inchiriereelicoptere.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160890531206c0---lovixugumozopatuwumaza.pdfIn PDF document text
    • http://extreamtuning.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160a4b02d2b332---96206792468.pdfIn PDF document text
    • http://abnicum.com/files/file/2524739630.pdfIn PDF document text
    • http://luckyassessoria.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1608414c2caaba---fezekureboboduvejafaludu.pdfIn PDF document text
    • https://www.sidertest.it/wp-content/plugins/formcraft/file-upload/server/content/files/160bfd0b256b79---99024537362.pdfIn PDF document text
    • http://fernandopelosini.it/userfiles/files/zefaxa.pdfIn PDF document text
    • http://www.fullertherapy.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c1846c17d6a---wugawasibet.pdfIn PDF document text
    • https://gz-topstar.com/wp-content/plugins/super-forms/uploads/php/files/5a35d5db50a37cf8f96ddb8c02f6fba0/34535579177.pdfIn PDF document text
    • http://hilltop1976.com/clients/24685/File/welepodokuwobodesu.pdfIn PDF document text
    • http://grupomarsamo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608af168c5d09---14345649912.pdfIn PDF document text
    • http://dailygiasi.com/uploads/userfiles/file/2649401815.pdfIn PDF document text
    • https://www.dentaltaxpros.com/wp-content/plugins/super-forms/uploads/php/files/10a55897034459252c5ce26032fd070c/gupexirinoxisumekeji.pdfIn PDF document text
    • http://4grd.com/cmsimages/file/tawidise.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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000194fe.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x194FE 18688 bytes
SHA-256: 25635f987d0be0396b59a4e64591e2f039e069b36bd9598aeaaeb056392fd8a5
font_01_sfnt_off0001b2ec.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1B2EC 10444 bytes
SHA-256: 12ea81f8b7856b6d9c099a429f8be910e0f92d60855d247124ef59d25e10597b
font_02_sfnt_off0001ca99.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1CA99 17464 bytes
SHA-256: 03bc96744e662519837997b90dd329e18c9fe1a3a08aecea3857d84079bd2939
font_03_sfnt_off0001f88a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1F88A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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