Malicious PDF — malware analysis report

Static analysis result for SHA-256 a90bd87f99ecb8b8…

MALICIOUS

PDF

71.7 KB Created: 2021-09-21 08:57:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 856f0da45b54ba1c438515d6b57f04f4 SHA-1: acb6778b79ab2f08da229347412e2e50dbaef3d5 SHA-256: a90bd87f99ecb8b82a7e552bfa6631a0e016008de75a623f32c414742cdf4930
96 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many of which point to disposable domains or compromised WordPress sites, indicating a link farm designed to redirect users. The ML classifier strongly flagged this PDF as malicious, and the presence of multiple PDF-specific heuristics related to URI and link farms supports this assessment. The primary purpose appears to be directing users to potentially malicious or phishing content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

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://coretry.ru/uplcv?utm_term=google+weather+widget+android+download PDF link annotation
    • http://okna-stv.ru/userfiles/files/pivilufegexe.pdfIn PDF document text
    • http://jolanyee.com/upload/files/202109062152433929.pdfIn PDF document text
    • http://geofer.eu/userfiles/files/dojuziriparesigu.pdfIn PDF document text
    • http://vngo-cc.vn/cooker/public/files/43718856557.pdfIn PDF document text
    • http://neoneophytou.com/ckfinder/userfiles/files/wojuguxadale.pdfIn PDF document text
    • http://hatowo.com/app/webroot/uploads/files/63116796934.pdfIn PDF document text
    • https://elicopter-de-inchiriat.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1613deb055e869---mutuzitupux.pdfIn PDF document text
    • http://apisicul.com/userfiles/files/dibejuwowumixusasakox.pdfIn PDF document text
    • http://gwtcs.org/Content/uploads/files/18915180969.pdfIn PDF document text
    • https://www.chortho.co.uk/wp-content/plugins/super-forms/uploads/php/files/lu28c8dd3qpekvkua6leet1c5t/bugabewalafite.pdfIn PDF document text
    • https://lapalettedesarts.fr/gestion/file/kepiragidaforobakozulun.pdfIn PDF document text
    • http://www.nisbd.com/wp-content/plugins/formcraft/file-upload/server/content/files/16136e9ef5d842---potorikifan.pdfIn PDF document text
    • http://tuderprogettazione.it/userfiles/files/67754585091.pdfIn PDF document text
    • https://kattliv.com/kattliv/admin/userfiles/file/wibomez.pdfIn PDF document text
    • http://dieukhactransam.com/uploads/files/jemexijaf.pdfIn PDF document text
    • http://kiajihlava.cz/UserFiles/File/rupifofupupagi.pdfIn PDF document text
    • http://yugreat.com/filespath/files/20210902112817.pdfIn PDF document text
    • https://grandplaza.bg/uploads/assets/file/92892589057.pdfIn PDF document text
    • https://flcevent.fcu.edu.tw/plugin/ce1/ckfinder/userfiles/files/20210902041916.pdfIn PDF document text
    • http://automozg.by/upload/editor/files/30696986918.pdfIn PDF document text
    • http://nbc.ua/design/pic/file/36064217247.pdfIn PDF document text
    • https://www.syah.org/wp-content/plugins/super-forms/uploads/php/files/b459b3fd2b5e5f4352e8b63002b496a7/tapatudoxefonopexiwu.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_off0000b73a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB73A 10484 bytes
SHA-256: 7c5c10b8ef05a9f53dc637b352a59cfd9dc8a4b9f5a31ad276b6266734755f3b
font_01_sfnt_off0000cee0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCEE0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e6f2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE6F2 16440 bytes
SHA-256: 587e91bd4b32565815f65e06f2d76edab97b498de18440979a3a03e28e348d69