Malicious PDF — malware analysis report

Static analysis result for SHA-256 751cda3a64fec317…

MALICIOUS

PDF

84.5 KB Created: 2021-10-05 17:25:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 85246fd9d888d7a930662e6f5e942df9 SHA-1: 6d4f2be19ba27a0359381654c80c1424aaa7769b SHA-256: 751cda3a64fec317822814ba52a738666168a677f51029e0bc33283f5d82a9f8
96 Risk Score

Malware Insights

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

The PDF contains a link farm pointing to numerous domains, with several heuristics indicating suspicious hosting and potential compromise. The ML classifier strongly flagged this PDF as malicious. The document body is largely unreadable binary data, offering no direct clues to its intent beyond its structure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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://musthighschool.mn/ckfinder/userfiles/files/76914018845.pdf In PDF document text
    • http://zhizhencn.com/filespath/files/20210926042712.pdfIn PDF document text
    • http://logtech.cz/foto/Image/file/mozelesusugegav.pdfIn PDF document text
    • https://yifff.se/userfiles/file/51389349123.pdfIn PDF document text
    • http://santehnika34.ru/images/file/puwagikaminenuvupuf.pdfIn PDF document text
    • http://siblom.ru/files/upload/file/95580538703.pdfIn PDF document text
    • http://saluteebenesseresas.it/userfiles/files/83973246993.pdfIn PDF document text
    • http://asijskepotraviny.cz/files/file/87158128986.pdfIn PDF document text
    • http://elcolono.net/userfiles/files/25665188134.pdfIn PDF document text
    • http://tc-antey.ru/uploads/files/72452548266.pdfIn PDF document text
    • http://gt-outillages.fr/ressource/site-image/files/9713078431.pdfIn PDF document text
    • https://sarenpinler.com/calisma2/files/uploads/44775526730.pdfIn PDF document text
    • http://cdn.eagle.mn/uploads/userfiles/files/gozolugujeliwad.pdfIn PDF document text
    • http://host.keraladreamhomes.com/~viswabrahmathach/admin/fckeditor/editor/filemanager/connectors/php/userfiles/file/55307236798.pdfIn PDF document text
    • http://szentimresiklos.hu/upload/file/63450531127.pdfIn PDF document text
    • https://alpinismbihor.ro/app/webroot/files/userfiles/files/93531003241.pdfIn PDF document text
    • https://ohcsi.com/ckfinder/userfiles/files/lafidofalavumela.pdfIn PDF document text
    • http://for-rent-antwerp.com/wp-content/plugins/formcraft/file-upload/server/content/files/16144d504c7566---ropetenelobax.pdfIn PDF document text
    • https://familienbilstrup.dk/ckfinder/userfiles/files/70745232660.pdfIn PDF document text
    • https://ahirealty.in/admin/userfiles/files/fezuvusubizadigavipifanu.pdfIn PDF document text
    • https://nailseasupportgroup.com/wp-content/plugins/super-forms/uploads/php/files/572b1532faaebc58aa8f37a9f267410d/58521461295.pdfIn PDF document text
    • http://global-poseg.com/wp-content/plugins/formcraft/file-upload/server/content/files/161356421d48e0---pinuvowi.pdfIn PDF document text
    • http://tlw.ro/UserFiles/file/vifibokiz.pdfIn PDF document text
    • http://pharmabiosolutions.com/filespath/files/20210909165503.pdfIn PDF document text
    • https://cyc-catering.pe/disac/userfiles/file/zetizoluzubifebita.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1KS0DP0cxss/uplcv?utm_term=high+pitched+ringing+in+right+ear+meaningPDF 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_off0000e82a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE82A 17212 bytes
SHA-256: d98a3462f35cd3b7f386cc5b25ec83d30e6487f2b44feb30891a72340fe27f29
font_01_sfnt_off00011450.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11450 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012c67.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12C67 10616 bytes
SHA-256: 3fa58d85223a0a3b0c0b178bdab26407299d7fbc3231e06678ffd38a73d8f6db