Malicious PDF — malware analysis report

Static analysis result for SHA-256 25ff3567755db388…

MALICIOUS

PDF

85.0 KB Created: 2021-09-07 11:30:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: f4e13cd0bde1c8a29d86caa71b50ddf9 SHA-1: 246cfd7fede014cf5f01212a643888c9cfc36f84 SHA-256: 25ff3567755db388e7ff32cfc186c758757be137b43026aee777f600bf44c5ac
96 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs pointing to various domains, many of which appear to be compromised or disposable hosting. The ML classifier strongly indicated maliciousness, and the heuristic firings suggest this PDF acts as a link farm, likely to distribute further malicious content or for SEO spam. No scripts were extracted from this sample.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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 https://inwebjor.ru/uplcv?utm_term=present+simple+and+present+continuous+examples+pdf PDF link annotation
    • https://miaousland.fr/ckfinder/userfiles/files/1606847526.pdfIn PDF document text
    • https://dichvuketoansg.com/luutru/files/52873702040.pdfIn PDF document text
    • https://alfa-clining.ru/wp-content/plugins/super-forms/uploads/php/files/bcf2d9da693e2d2652ecf8c11cf36b02/93383684006.pdfIn PDF document text
    • http://www.realisthotel.com/wp-content/plugins/formcraft/file-upload/server/content/files/160f9aeb0df8d4---90044576683.pdfIn PDF document text
    • http://rkmaster.ru/uploads/files/fajipimavodif.pdfIn PDF document text
    • http://vdadanang.vn/app/webroot/assets/files/31853541088.pdfIn PDF document text
    • https://parisautotravel.com/wp-content/plugins/super-forms/uploads/php/files/psp9siqccbm7atroes2avfo342/rudiruva.pdfIn PDF document text
    • https://aymfly.com/aym_image/files/45163612786.pdfIn PDF document text
    • http://rintrans.com/files/vukareziwojuxe.pdfIn PDF document text
    • https://dukra.sk/editor_uploads/files/widasatufuminogugikod.pdfIn PDF document text
    • https://ecoinkworld.com/wp-content/plugins/super-forms/uploads/php/files/3620eb1e8fdd8d4aa0f627cc042eeaab/xeridowidunotixorisemovod.pdfIn PDF document text
    • http://www.fotografoeventimilano.com/wp-content/plugins/formcraft/file-upload/server/content/files/160fb265763b06---595192037.pdfIn PDF document text
    • https://cylinder96.ru/admin/ckfinder/userfiles/files/pixazewuvivalagaju.pdfIn PDF document text
    • https://ailani.org/wp-content/plugins/super-forms/uploads/php/files/88ea66cfeb7a78707b18b5e9447cd162/suzapanufu.pdfIn PDF document text
    • https://adverto.ee/userfiles/file/99858707813.pdfIn PDF document text
    • http://ophtalmic-overnight.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160f187e0c7540---59723668162.pdfIn PDF document text
    • https://jclifeschools.org/wp-content/plugins/super-forms/uploads/php/files/043f48015f19b3183094bfb4e2a5f852/pizixetuxujalefebakitibo.pdfIn PDF document text
    • https://dacinsara.ro/fckfiles/file/xitojodo.pdfIn PDF document text
    • https://reitinguok.lt/userfiles/file/99421489812.pdfIn PDF document text
    • http://begemot-rus.com/uploadfiles/file/2021051416333873499.pdfIn PDF document text
    • http://footstepfloor.com/upfiles/files/5296786668.pdfIn PDF document text
    • https://nuevocoach.co.uk/wp-content/plugins/super-forms/uploads/php/files/25a96ce3c126943bec331f858ab6b47d/kixejogixupuroduzikipul.pdfIn PDF document text
    • http://cabanagarden.hu/editor_up/83360725507.pdfIn PDF document text
    • http://www.salac.cz/ckfinder/userfiles/files/dovotima.pdfIn PDF document text
    • https://www.booster-p.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e47e824beb5---nuributun.pdfIn 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://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_off0000e502.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE502 18084 bytes
SHA-256: 380c87c07cb9d60baa4dfd8fcb843c81a94ec048013912cb679ccf6d27fa06c3
font_01_sfnt_off000113ff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x113FF 10984 bytes
SHA-256: 1637e9d42ee3497f0332ae09ad73c46a501013dbe9b9351edbe9b1d6f2188c27
font_02_sfnt_off00012d85.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12D85 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1