Malicious PDF — malware analysis report

Static analysis result for SHA-256 81c3f97df7524a4f…

MALICIOUS

PDF

86.6 KB Created: 2021-09-08 09:13:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 9a1b6455db5734582589034dd3442c0c SHA-1: af0654d34d24259ec23410d2755b3e6cca5c4858 SHA-256: 81c3f97df7524a4f2e8873d89c894d8db85f3746783b110a573a7eb5b5f26b73
164 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier. It contains embedded JavaScript and numerous external links, many pointing to compromised CMS uploads or disposable hosting, suggesting it functions as a link farm to distribute malicious content or phish users. The presence of embedded JavaScript indicates an attempt to execute code, likely to facilitate further malicious activity.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9905

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://krisoc.ru/uplcv?utm_term=toughest+tongue+twisters+pdf PDF link annotation
    • http://esthebel.de/userfiles/file/bejaxumukexidesunosiwobo.pdfIn PDF document text
    • http://miamiwars.pl/wp-content/plugins/super-forms/uploads/php/files/1ddefd02fa9e4362a0f997d424ec5e73/vilibikezi.pdfIn PDF document text
    • http://vo23.ru/upload/file/tibenom.pdfIn PDF document text
    • http://parkwestresidences.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b903b8f29f6---vukavi.pdfIn PDF document text
    • https://rittenhousesmiles.com/wp-content/plugins/super-forms/uploads/php/files/8015747cb5f3370e77e5d10c5b755002/11186528508.pdfIn PDF document text
    • http://fygl.net/uploads/file/29213148402.pdfIn PDF document text
    • http://k-yoga.org/file_upload/spaw_upload/file/20210619144026.pdfIn PDF document text
    • http://flygarfield.net/userfiles/file/fitusabunizowipemepazu.pdfIn PDF document text
    • http://monterroso-construpuntos.com/campannas/file/mimizafuve.pdfIn PDF document text
    • http://hueide.com/upload/files/vivebaviwi.pdfIn PDF document text
    • http://aire-limpio.com/img/editor/file/fexebusonatuzixi.pdfIn PDF document text
    • https://creativesilhouettes.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160c889c77fb10---noripotuzazulavevozovaf.pdfIn PDF document text
    • https://earthideasawnings.com/wp-content/plugins/formcraft/file-upload/server/content/files/160df516142605---84158105464.pdfIn PDF document text
    • http://www.agrosystem.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/1607cd8e707fb0---76019118617.pdfIn PDF document text
    • https://mkting.com.co/wp-content/plugins/super-forms/uploads/php/files/e524111865aa369317994f661df19723/gexinojikovogasu.pdfIn PDF document text
    • https://www.campacinter.com/image/upload/File/89461077078.pdfIn PDF document text
    • http://www.ramseier-appenzell.ch/elrada/js/ckfinder/userfiles/files/89366828628.pdfIn PDF document text
    • http://okazionche.com/files/lijefamazerorizaxap.pdfIn PDF document text
    • https://xlspandoek.nl/userfiles/file/tomazokudagi.pdfIn PDF document text
    • http://1984wnhs.com/clients/2/25/250e0aaa51dad033202e6c34d8602b4d/File/4827304956.pdfIn PDF document text
    • http://www.lentilles-progressives.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160b10f9890fc9---neruzatuwalobinuxupotubi.pdfIn PDF document text
    • https://fortlauderdale-carservice.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609828651b370---63319674523.pdfIn PDF document text
    • http://massarentearchitettura.com/userfiles/files/nifafujapepazexo.pdfIn PDF document text
    • http://lnyuanzong.com/uploads/files/20210807034545.pdfIn PDF document text
    • http://bodemveenweiden.nl/bodem-veenweiden-img/fixeriteta.pdfIn PDF document text
    • http://chanhbon.vn/media/ftp/file/vefosorofabanudodutejo.pdfIn PDF document text
    • https://livingcircles.ch/wp-content/plugins/formcraft/file-upload/server/content/files/160968306d1724---xibedesajipudinen.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ea0f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA0F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010226.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10226 10716 bytes
SHA-256: 05cdb083b5a52983adf6ad77070c27ee961fdb5181b4356d7de9b469a3de5081
font_02_sfnt_off00011a92.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11A92 19000 bytes
SHA-256: 296eca450044ec7820e3e01e9679917d46cadb3cff3a86d2fb4f931134e7a98b

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