Malicious PDF — malware analysis report

Static analysis result for SHA-256 35ee259bc7e5b622…

MALICIOUS

PDF

81.2 KB Created: 2021-10-08 04:58:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 38d3053a3d5cbf2a9a4b03567c873a0f SHA-1: ac7db614202c40269406375ee4d8d590ab3aa0cd SHA-256: 35ee259bc7e5b62256ff81a32e14d04c297b5c6cc6ad4760240172986e37bf49
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous links, many pointing to compromised CMS uploads or disposable hosting, suggesting a link farm designed to redirect users. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing content but likely serving as a vessel for these malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9949

Heuristics 6

  • 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.
  • 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://sooclose.eu/upload/File/67102390012.pdf In PDF document text
    • http://geluidsadviesnederland.nl/ckfinder/userfiles/files/57816630111.pdfIn PDF document text
    • http://moveisgarciadigital.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1615d88ee8a311---zudivasiladojuxewit.pdfIn PDF document text
    • http://laibros.com/ckeditor/userfiles/files/wevimepu.pdfIn PDF document text
    • http://www.cascinasorigherio.it/wp-content/plugins/formcraft/file-upload/server/content/files/1614b849b791f5---21565810390.pdfIn PDF document text
    • https://implantsdentairesdesmoulins.com/upload/editor/file/41415313580.pdfIn PDF document text
    • https://nhaban24h.com.vn/wp-content/plugins/super-forms/uploads/php/files/68p09mrtatbki083vdf7mfu0e2/madeleromizuza.pdfIn PDF document text
    • https://typeone.com.my/ckfinder/userfiles/files/rokalizididivuleturid.pdfIn PDF document text
    • http://nuovojob.com/userfiles/files/nimujiraxalofusimubivodi.pdfIn PDF document text
    • https://hoffmanowska.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1613cb3a74b6e8---fevubebobitogumafibig.pdfIn PDF document text
    • http://peak-experience-japan.com/images/blog/file/82918397220.pdfIn PDF document text
    • https://otomatcilarmetal.com/otomat/upload/files/vaduzoxoxel.pdfIn PDF document text
    • https://chuyennhakienvangvn.net/upload/files/verepoje.pdfIn PDF document text
    • https://optimuselearningschool.com/learning/site/images/uploadfiles/49102444844.pdfIn PDF document text
    • http://zkmeiqi.com/admin/ckfinder/upfile/files/27360992426.pdfIn PDF document text
    • https://mariellatriolo.it/public/file/bamunerenasakeririjeruj.pdfIn PDF document text
    • https://egc.ecrom.work/syo/files/xavuwex.pdfIn PDF document text
    • http://studiomarazzi.eu/userfiles/files/95001309391.pdfIn PDF document text
    • https://metnar.pl/web/uploads/files/71578572791.pdfIn PDF document text
    • https://alenakovalchuk.ru/wp-content/plugins/super-forms/uploads/php/files/a0425a3647d203c88b1ff46002e47987/59616605684.pdfIn PDF document text
    • http://www.realisthotel.com/wp-content/plugins/formcraft/file-upload/server/content/files/16132e5d0911ac---16159358059.pdfIn PDF document text
    • https://dptech.vn/uploads/files/mumumomoxowanoxifo.pdfIn PDF document text
    • https://www.antoniopopolizio.it/ckfinder/userfiles/files/74071080028.pdfIn PDF document text
    • https://annekienlen.fr/imagesfile/90138348040.pdfIn PDF document text
    • https://shotclock.ca/wp-content/plugins/super-forms/uploads/php/files/d745a2e7eba2287a40d4ce893ebbdf78/zuwowu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/A3Ryygt5BCM/uplcv?utm_term=nauseated+for+a+weekPDF 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_off0000d9ee.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9EE 17572 bytes
SHA-256: a2294ae3f3a356c62a4f8833c08b5aefd1bad77bdf4516a619fbf99dc5304fd4
font_01_sfnt_off000107ef.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x107EF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012006.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12006 10360 bytes
SHA-256: 4b6b102fd8c620a5f1f2fda1372c8cadc88023ab7f9db53f697881009eaba781

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