Malicious PDF — malware analysis report

Static analysis result for SHA-256 8585a0e6decf9501…

MALICIOUS

PDF

85.5 KB Created: 2021-09-07 16:23:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: d7c27f1e4e6e7b7c854a3764cdd9f734 SHA-1: 370d022ca264bb6ea73b97839803fc911029ca93 SHA-256: 8585a0e6decf9501e33c21af0f7ea917989e9e804890512a2724ce7df39e696d
96 Risk Score

Malware Insights

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

The PDF file contains numerous embedded URLs, many of which point to compromised WordPress sites or disposable hosting, indicating a link farm designed to redirect users. The ML classifier strongly flagged this PDF as malicious, and the presence of multiple external URIs suggests an attempt to lure users to potentially harmful external content. The document body is heavily obfuscated and appears to be non-readable content generated by wkhtmltopdf, providing no direct user-facing lure.

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://irlanc.ru/uplcv?utm_term=surface+preparation+for+coating+pdf PDF link annotation
    • https://rhdplumbing.com/wp-content/plugins/super-forms/uploads/php/files/c30503477f2d24888199832a639f7b66/38487276148.pdfIn PDF document text
    • http://mueblesdepladur.es/1/userfiles/file/56687012891.pdfIn PDF document text
    • https://www.andyselfstorage.co.uk/wp-content/plugins/super-forms/uploads/php/files/t3520an55meuqqr0j1jksunics/togebivemugep.pdfIn PDF document text
    • https://www.osteopathe-montpellier-sud.fr/ckfinder/userfiles/files/saxid.pdfIn PDF document text
    • http://smartmedicaleg.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b0b298317c9---25578198976.pdfIn PDF document text
    • http://santeh.md/img/files/zezasolajeduxovikusurab.pdfIn PDF document text
    • http://2m-m.eu/userfiles/files/sowenivetomotibubekemajuf.pdfIn PDF document text
    • http://unsersohn.com/images/file/puzotan.pdfIn PDF document text
    • https://www.schroedersales.com/wp-content/plugins/super-forms/uploads/php/files/06a296109b194dc2cf55932dec34a490/zetabuvamefap.pdfIn PDF document text
    • https://tamtam.com.ua/wp-content/plugins/super-forms/uploads/php/files/432f8c8411e332c18f0b7910451d2615/36540774160.pdfIn PDF document text
    • https://goactive.hu/wp-content/plugins/super-forms/uploads/php/files/7cf0f046515ad5f4aceb5bd620d793d7/39020184389.pdfIn PDF document text
    • https://damsindia.org/admin/uploads/file/1258666651.pdfIn PDF document text
    • https://chicagoportablexray.com/wp-content/plugins/formcraft/file-upload/server/content/files/160dfe6679cd9b---boxafiga.pdfIn PDF document text
    • https://www.escon.it/wp-content/plugins/super-forms/uploads/php/files/1acc5bec7cde02f1de16ff6582fb2ac9/49537535760.pdfIn PDF document text
    • https://www.a2zmedical.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1611d89229dbf7---vijutiveremigurawi.pdfIn PDF document text
    • http://gyobel.it/public/file/2151694436.pdfIn PDF document text
    • https://klingende-zeder.de/wp-content/plugins/formcraft/file-upload/server/content/files/1608456f5da3fa---30886668777.pdfIn PDF document text
    • http://www.lbf-cosmetics.com/website/wp-content/plugins/formcraft/file-upload/server/content/files/1607bc6fe9ae40---xitute.pdfIn PDF document text
    • https://abugfreemind.com/userfiles/file/78839214188.pdfIn PDF document text
    • http://bakoca.hu/files/file/nobajaxukikal.pdfIn PDF document text
    • http://www.expertnutritionadvisor.com/wp-content/plugins/formcraft/file-upload/server/content/files/16097e0cd30c0f---59505711639.pdfIn PDF document text
    • https://monuments-msk.ru/wp-content/plugins/super-forms/uploads/php/files/f2a4359f8fc600109d7c646e33f3c43b/24405748441.pdfIn PDF document text
    • https://djhelaly.com/wp-content/plugins/super-forms/uploads/php/files/d994aa2271849c4ad2b3b74792d87ffd/56838127858.pdfIn PDF document text
    • https://locktactyuma.com/userfiles/file/9512501731.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_off0000ed83.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED83 16476 bytes
SHA-256: 406385f2c29119db32f262474713403d8cb23fe9582b64e8b1b19a6f0943a633
font_01_sfnt_off000117a9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x117A9 10756 bytes
SHA-256: 639784590e218684ecbd3502c3194c77504c395015b03c06a3b6d7f10bb2a1db
font_02_sfnt_off00013057.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13057 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1