Malicious PDF — malware analysis report

Static analysis result for SHA-256 c10bb4983276df33…

MALICIOUS

PDF

71.0 KB Created: 2021-06-24 05:36:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-11
MD5: 0f914ef421ceb888b09e5785f554b5b7 SHA-1: 5cbe7669d15d604c531f7641bb72c897f6be8ad9 SHA-256: c10bb4983276df33765dafa25c7a96214be99bb13efb79242faf0fb0f50a9763
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The sample is a PDF document that leverages a link farm hosted on compromised WordPress sites, masquerading as a PDF converter. The ML classifier and ClamAV detection strongly indicate malicious intent, likely to deliver a phishing payload or malware. The presence of multiple external URIs suggests an attempt to redirect the user to a malicious download or phishing page.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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=mb+to+pdf+converter PDF link annotation
    • https://www.ferienhof-schneider.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607c3068733b6---91078490530.pdfIn PDF document text
    • http://hanhthien.net/uploads/file/57062637287.pdfIn PDF document text
    • https://vernadoc.com/wp-content/plugins/super-forms/uploads/php/files/e7e5c8b6aff99fadb6020a387ec36d6c/sexazibojo.pdfIn PDF document text
    • https://drmarlenebothma.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/1608f4e99f292d---47213300046.pdfIn PDF document text
    • https://rumputhijau.com/contents//files/deduzajadavesovajerevi.pdfIn PDF document text
    • http://adamlegal.com/userfiles/file/90639758610.pdfIn PDF document text
    • https://harkakotony.hu/UserFiles/file/70037916002.pdfIn PDF document text
    • http://accessiblevehicleservices.com/userfiles/file/91328952379.pdfIn PDF document text
    • https://yarsan.ru/wp-content/plugins/super-forms/uploads/php/files/b0bc6cfba933182b75e62894b03aa6b1/96091652953.pdfIn PDF document text
    • http://aaaexpressheating.com/userfiles/file/33475698282.pdfIn PDF document text
    • https://chocoinmobiliario.com/wp-content/plugins/super-forms/uploads/php/files/b6fc16e0060a8c1f5acc3b04d3ed9d13/badefisawutokidun.pdfIn PDF document text
    • https://claphamjunction.com.au/wp-content/plugins/super-forms/uploads/php/files/f9de5b3e109023d660048d560859f897/29715464990.pdfIn PDF document text
    • https://terravistahometeam.com/wp-content/plugins/super-forms/uploads/php/files/0af9c772de1bcbbbe00e36fd5bfb22ec/90342778061.pdfIn PDF document text
    • https://kfz-gutachter-oliver-schiller.de/wp-content/plugins/formcraft/file-upload/server/content/files/160738cc107991---12995502857.pdfIn PDF document text
    • https://www.hadlowsecurityshutters.com/wp-content/plugins/super-forms/uploads/php/files/94108756f2819beaf7d01e7e0adff027/zisimulowire.pdfIn PDF document text
    • http://www.atrium-tuiles.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608f93c630b66---57509760722.pdfIn PDF document text
    • http://www.hypnotiseur.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b8ac96ad37e---jamazuwoduwapug.pdfIn PDF document text
    • https://thefertilizerequipment.com/d/files/48012122034.pdfIn PDF document text
    • http://lezeckastenakosice.sk/upload/files/42987211539.pdfIn PDF document text
    • https://georgiamusicpartners.org/wp-content/plugins/super-forms/uploads/php/files/b5a317e8e52431ccd7a660c85f072561/fugamuxejisak.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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_off0000da52.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA52 4932 bytes
SHA-256: f4e2890ea21629e13ae226b5ed9608b62773bd26b1a3e2c0de2dcc2e6706ee1d
font_01_sfnt_off0000eb42.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB42 10632 bytes
SHA-256: 1e2a529c52b8a69d1c8557b9d2afb2cfc8837c6fac77064b8eca5ecf8d15e575

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