Malicious PDF — malware analysis report

Static analysis result for SHA-256 428b4dd075d20bb2…

MALICIOUS

PDF

76.4 KB Created: 2021-08-28 03:31:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 97ab62deacb288d488a6640b32e32332 SHA-1: 74cf9debc87d7e76648ca7ec03ced03b6bd8bb25 SHA-256: 428b4dd075d20bb28ed190dde627abcb248cbb98ecc7ee4bad34665c61613bad
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF document contains embedded JavaScript and numerous external links, many of which point to compromised WordPress sites or disposable hosting. These links likely serve as a link farm to redirect users to phishing pages or download further malicious content. The ML classifier and ClamAV detection strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9995

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 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 http://nguoigiupviec99.com/webroot/img/files/14622746688.pdf In PDF document text
    • https://pu-sk.com/app/templates/js/ckfinder/userfiles/files/35921319837.pdfIn PDF document text
    • https://aldea.work/wp-content/plugins/super-forms/uploads/php/files/4de4c83d1d26de506e00e42e93fc6b9c/gugaduvujuwa.pdfIn PDF document text
    • https://www.harasportcenter.com/wp-content/plugins/super-forms/uploads/php/files/0j68tgvg69srbmtqg8qrnh1jq4/75739807271.pdfIn PDF document text
    • https://actorconseil.com/files/file/81156463632.pdfIn PDF document text
    • https://specialbrands.gr/wp-content/plugins/super-forms/uploads/php/files/18d2b68a9bbe8788ad0b4a8eb67922bf/58846621597.pdfIn PDF document text
    • http://cdmatik.com/uploads/file/sukiwasunep.pdfIn PDF document text
    • http://markasib.ru/ckfinder/userfiles/files/vubenem.pdfIn PDF document text
    • http://hengfengpaper.com/filespath/files/20210813151031.pdfIn PDF document text
    • https://stvorki.ru/files/file/rezebelexo.pdfIn PDF document text
    • https://www.saltriot.com/wp-content/plugins/super-forms/uploads/php/files/f967c078604cae784a1ccce2d4e15f5f/17877351450.pdfIn PDF document text
    • http://israel-aliya.com/wp-content/plugins/super-forms/uploads/php/files/e9d0c12dec834be77ed5c0e921e722c5/69141974130.pdfIn PDF document text
    • https://www.carlosfunes.es/wp-content/plugins/formcraft/file-upload/server/content/files/16078df795b3f7---84661294327.pdfIn PDF document text
    • http://photou.cc//ckfinder/userfiles/files/73581441723.pdfIn PDF document text
    • http://hoangle.vn/uploads/userfiles/file/65579627313.pdfIn PDF document text
    • http://buyyoutubecomments.com/ci/userfiles/files/33350008606.pdfIn PDF document text
    • http://jkbprivateiti.com/userfiles/file/texazivuzaku.pdfIn PDF document text
    • http://mountmedpharmacy.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160785da2e4c40---36527269077.pdfIn PDF document text
    • http://www.zywawiara.pl/pliki/57827566662.pdfIn PDF document text
    • http://hytechplus.com/userfiles/file/nekirimozamajixagupajepe.pdfIn PDF document text
    • http://gardnersunited.com/clients/e/eb/eb3320446930dd457027df34457c622b/File/mokatijufu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/GLLx1DTH0VQ/uplcv?utm_term=esther+amini+concealedPDF 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_off0000c5ae.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC5AE 17540 bytes
SHA-256: 93521274036d12af319dce126fbb7d975a51bfedfb37f4570b53506009c48d16
font_01_sfnt_off0000f376.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF376 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010b8d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10B8D 10620 bytes
SHA-256: b1c1275f8a3ce20116eb167e2633644377ba2504356c1d199814df3fbb212794

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