Malicious PDF — malware analysis report

Static analysis result for SHA-256 539ffe3b55707c02…

MALICIOUS

PDF

73.6 KB Created: 2021-09-22 23:31:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 5ebf1a01e3d3c5bc44142df8ba7d3c1d SHA-1: 2ca0895cd621ec677f9a8bd1c54a2239be52358b SHA-256: 539ffe3b55707c02bd282f70a77a874edddaee8cb622b643420fc99a19d2921d
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded links pointing to external resources, many of which are hosted on compromised CMS uploads or disposable domains, suggesting a link farm for distributing further malicious content. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware distribution. No scripts were extracted, but the PDF structure itself is used to host and redirect to other malicious files.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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.
  • 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 http://www.iece.in/userfiles/file/rowotowizilubobopak.pdf In PDF document text
    • http://eugensa.lt/app/webroot/uploads/userfiles/files/36991038662.pdfIn PDF document text
    • http://wsystem.sk/userfiles/files/20965068575.pdfIn PDF document text
    • http://bigbazar.cz/is/images/FCKeditor/File/kevisamep.pdfIn PDF document text
    • http://shimamura-mail-order.com/userfiles/file/sawal.pdfIn PDF document text
    • http://motopujcovnateplice.cz/userfiles/file/99978591187.pdfIn PDF document text
    • http://drivingtesttips.ie/fckeditor/userfiles/file/zorun.pdfIn PDF document text
    • https://hkpefa.org/editor_upload/file/66533951718.pdfIn PDF document text
    • http://talk200.com/admin/admin/uploadfiles/file/daxidozetekitejero.pdfIn PDF document text
    • https://leo.tw/upload/ckeditor/files/barenidabuvomisadozusen.pdfIn PDF document text
    • http://superazs.ru/images/news/file/vesixos.pdfIn PDF document text
    • http://kelakewangshangduchang.a9188.com/upload_files/art_files/files/20210904_123803.pdfIn PDF document text
    • https://intelean.com/wp-content/plugins/formcraft/file-upload/server/content/files/161407d8d89328---zudivudamisawozib.pdfIn PDF document text
    • https://www.chauffeur-prive-nice.fr/wp-content/plugins/formcraft/file-upload/server/content/files/16138c93ac2646---20617561647.pdfIn PDF document text
    • https://empresa-venta.hr/files/jowuve.pdfIn PDF document text
    • http://prasongp.com/file_media/file_image/file/tixurap.pdfIn PDF document text
    • http://agataklimowska.pl/userfiles/file/sewawejibege.pdfIn PDF document text
    • https://www.accidentinjuryalbuquerque.com/wp-content/plugins/super-forms/uploads/php/files/q5u3cc58d92b51mo57lauuupmn/deler.pdfIn PDF document text
    • http://adhdesign.de/userContent/files/20210906142319-78327629195.pdfIn PDF document text
    • http://ambulatorioveterinariovianello.eu/userfiles/files/20037850127.pdfIn PDF document text
    • http://aloisiquadri.it/userfiles/files/pozireg.pdfIn PDF document text
    • http://rewitex.pl/userfiles/file/pareguxelomu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=samurai+way+of+the+warrior+mod+apk+downloadPDF link annotation
    • 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_off0000b903.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB903 17188 bytes
SHA-256: 58e517ae871aab5c1eb452449dc719290bada6a7a94d0fc03d9d608bef8575ea
font_01_sfnt_off0000e4f2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4F2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000fd09.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD09 11064 bytes
SHA-256: 96ba5487b66de761425511d2ec9cb6894a20234be733372a7d6f2b76c76b9636

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