Malicious PDF — malware analysis report

Static analysis result for SHA-256 9a1836743bcf7f48…

MALICIOUS

PDF

71.8 KB Created: 2021-09-25 10:38:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 0647852baf52b65d406c69a9d878af9c SHA-1: f83118877ac2e834914dd3370bf6b3a57f703982 SHA-256: 9a1836743bcf7f4871b5d0069fa16acf4cd50c0bcd3b50f842cf521fdaf02b3a
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by an ML classifier as malicious and contains numerous embedded URLs that form a link farm. Several of these URLs point to compromised CMS uploads or disposable hosting, indicating a likely attempt to redirect users to malicious sites. While no scripts were directly extracted, the structure and URL patterns are consistent with phishing or malware distribution lures.

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 https://istruttorecinofilo.it/userfiles/file/15271131963.pdf In PDF document text
    • https://duext.com/wp-content/plugins/super-forms/uploads/php/files/efce06aabc027908ff03ead1df914d30/89536842050.pdfIn PDF document text
    • https://happy-playground.gr/uploads/_uploads/files/rajagazukeba.pdfIn PDF document text
    • http://kamkmori.cz/ckfinder/userfiles/files/45439143869.pdfIn PDF document text
    • http://skoleniridicu-online.eu/ckfinder/userfiles/files/pagujaminibamatomanupi.pdfIn PDF document text
    • http://stoewebdesign.no/userfiles/file/jawafipafoduvo.pdfIn PDF document text
    • https://subarini.ro/mm/file/nilexizaxepasonajifalaw.pdfIn PDF document text
    • https://newegys.egyseg.eu/ckfinder/userfiles/files/mogagedivamiv.pdfIn PDF document text
    • https://prosaison.fr/userfiles/files/potabarobawedara.pdfIn PDF document text
    • https://saigonservices.vn/images/uploads/files/lubikomosizuw.pdfIn PDF document text
    • http://studiocalcinoni.com/userfiles/files/63569839687.pdfIn PDF document text
    • http://dylogistics.com/userData/board/file/tabup.pdfIn PDF document text
    • http://ammk.sk/userfiles/file/71906617039.pdfIn PDF document text
    • https://iohrp.org/f_files/files/77822188970.pdfIn PDF document text
    • http://kaplanpm.com/wp-content/plugins/formcraft/file-upload/server/content/files/161316aea6a3dc---98122750414.pdfIn PDF document text
    • https://kfk-dekoration.dk/images/uploadedimages/file/76840672762.pdfIn PDF document text
    • https://www.ideakliniksisli.com/wp-content/plugins/formcraft/file-upload/server/content/files/16142245acfee1---lokokunu.pdfIn PDF document text
    • http://gaongonmaiphuong.vn/webroot/img/files/27261916626.pdfIn PDF document text
    • https://al-wesam.com/userfiles/files/27570767923.pdfIn PDF document text
    • http://kidneytracker.com/ckfinder/userfiles/files/31525170333.pdfIn PDF document text
    • http://bangdinhphucat.com/quangbasanpham/app/webroot/upload/image/files/12778247019.pdfIn PDF document text
    • http://normel.org/files/upload/file/zefab.pdfIn PDF document text
    • https://kamwalibais.com/userfiles/file/vasisajotuxi.pdfIn PDF document text
    • http://dallapietamarchisio.it/userfiles/files/sixumamulodudanejogibijun.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=move+documents+to+sd+card+androidPDF 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_off0000b271.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB271 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ca83.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCA83 18272 bytes
SHA-256: 13c873fe0d3929b7f95c036b352cfbd04041878ce4e62d0d59473e6b4ef7485d
font_02_sfnt_off0000f969.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF969 10644 bytes
SHA-256: 1f59ef6abb1f6ed3799c662799a72649a276333eae0acf633e7c46ae62b8eb60