Malicious PDF — malware analysis report

Static analysis result for SHA-256 9cf5c6c5945fe459…

MALICIOUS

PDF

75.6 KB Created: 2021-09-03 06:35:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 113572bb9680cc55b48da0e223915820 SHA-1: fb7f82beaf521b222cfdbb252f1edb3911e84ce2 SHA-256: 9cf5c6c5945fe459fd879cc2710625d50a36376eac9bb08a8f36dea7fdf6c1bf
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a link farm with numerous URLs pointing to other PDFs hosted on compromised websites. This suggests a multi-stage attack where the initial PDF serves as a lure to redirect users to further malicious content. The ML classifier strongly indicated maliciousness, supporting this assessment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

Heuristics 5

  • 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://nuyewrecruitment.com/wp-content/plugins/super-forms/uploads/php/files/14ca25bf82c9d92ef72c3532822f0ce2/19113317620.pdf In PDF document text
    • http://kimkhimientrung.com/uploads/image/files/64378581204.pdfIn PDF document text
    • http://dbcasagayathottam.org/assets/uploads/cms_images/files/94434706722.pdfIn PDF document text
    • http://mega.kz/media/upload/files/pujetiw.pdfIn PDF document text
    • https://pinotcar.com/wp-content/plugins/super-forms/uploads/php/files/93bfbbf485092bfd2223ef19228a08ba/53201391391.pdfIn PDF document text
    • https://turkuazhost.com/calisma2/files/uploads/58389129580.pdfIn PDF document text
    • https://cashcruis.ru/wp-content/plugins/super-forms/uploads/php/files/6db67ee56261dd5e892b2a05500f52d3/paketo.pdfIn PDF document text
    • http://ljhalls.com/wp-content/plugins/super-forms/uploads/php/files/c0dedaaffce72a86301079aa64d99a9b/jedajajegunarag.pdfIn PDF document text
    • https://www.jemelectric.com/wp-content/plugins/formcraft/file-upload/server/content/files/160702ff4d0178---98985144730.pdfIn PDF document text
    • http://kristinanamaste.eu/files/zivakevepejiwipupaxub.pdfIn PDF document text
    • https://j-kowalewski.pl/uploads/userfiles/files/waxukef.pdfIn PDF document text
    • http://hondatayho.vn/images/ckeditor/files/18274622536.pdfIn PDF document text
    • https://teplitsyoptom.ru/wp-content/plugins/super-forms/uploads/php/files/75549a3d8e3f2ed599be22da4eb0e73a/rurerig.pdfIn PDF document text
    • http://autoshiftbid.com/fckeditor/userfiles/file/pelaxogubiw.pdfIn PDF document text
    • http://delawaretravelmedicine.com/wp-content/plugins/formcraft/file-upload/server/content/files/16085ea82ab1c5---tixemosawedofir.pdfIn PDF document text
    • http://www.aragonemprendedor.com/userfiles/files/bibeviz.pdfIn PDF document text
    • http://horizonpestservices.com/userfile/povadaxajevixegevire.pdfIn PDF document text
    • https://www.amiunaorchestra.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16097cc940dcb2---39041682811.pdfIn PDF document text
    • http://www.melodypods.com/wp-content/plugins/formcraft/file-upload/server/content/files/1610627adb94d2---77983091867.pdfIn PDF document text
    • https://aljazeerahdrilling.com/userfiles/files/96301078039.pdfIn PDF document text
    • http://studiobonvino.com/userfiles/files/pakopumitopewofuv.pdfIn PDF document text
    • http://on-call-anatomist.org/ckfinder/userfiles/files/wojodezesi.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/FevRqgeaUVY/uplcv?utm_term=circle+theorems+notes+pdfPDF 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_off0000c33f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC33F 17600 bytes
SHA-256: c5c6d24f1b0f2833713f11b257916a5fcffadd3c4f996b69ece9cd27619b7095
font_01_sfnt_off0000f06b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF06B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010882.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10882 10752 bytes
SHA-256: efff6167e7b78bd653a56d87792d2cc8597d3a1a21078d8f704d5aa66ebcc12d