Malicious PDF — malware analysis report

Static analysis result for SHA-256 81fd41661e416b98…

MALICIOUS

PDF

71.8 KB Created: 2021-09-02 22:00:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: cd4a564bc97280c5b0d2812e68aa445f SHA-1: ccf21b9b78a1ff5bf99b4c30ffb00919f7280d8d SHA-256: 81fd41661e416b9819ffe8b6bc621d12db9fb1340f24a7b2ef69d774f99ed748
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised CMS uploads or disposable hosting, indicating a link farm designed to distribute malicious content or phish users. The ML classifier and ClamAV detection strongly suggest malicious intent. The file's structure and URL patterns are consistent with a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://buddhavehicle.com/userfiles/file/xajezak.pdf In PDF document text
    • https://washlounge.in/ckfinder/userfiles/files/6702543271.pdfIn PDF document text
    • http://medrea.ru/upload/files/dizisob.pdfIn PDF document text
    • http://www.mondzorgvesa-voorschoten.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1607b4304b2123---desowedowe.pdfIn PDF document text
    • http://www.iuoelocal870.com/kaizen/ckfinder/userfiles/files/nevubabosekivule.pdfIn PDF document text
    • http://owv-sad.de/userfiles/files/48667047666.pdfIn PDF document text
    • http://sportsgarten.com/editorData/file/13615309239.pdfIn PDF document text
    • http://ekolojikweb.net/upld/userfiles/file/javesenunulosoxisinax.pdfIn PDF document text
    • https://kltccompany.com/ckfinder/userfiles/files/65261915133.pdfIn PDF document text
    • https://taechoclub.com/FileData/ckfinder/files/20210601_9774765BA28DBCCC.pdfIn PDF document text
    • https://www.frontierexim.com/wp-content/plugins/super-forms/uploads/php/files/ubjtkds86ald89rk193ik2koih/lisetijagibejan.pdfIn PDF document text
    • https://retentionstudentexperience.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ae3c578ba5a---fivugokugefuvi.pdfIn PDF document text
    • http://sciencevier.com/wp-content/plugins/formcraft/file-upload/server/content/files/160701026a5dc1---11325762672.pdfIn PDF document text
    • http://www.platformliften.info/wp-content/plugins/formcraft/file-upload/server/content/files/16079c7d51cf71---12247072082.pdfIn PDF document text
    • https://alate.org/admin/fckeditor/editorfile/20514513070.pdfIn PDF document text
    • http://czdashan.cn/uploadfile/file/2021051612455573499.pdfIn PDF document text
    • http://bsa-billiard.by/images_from_html_editor/file/siwonopage.pdfIn PDF document text
    • https://wotfiles.com/ckfinder/userfiles/files/garasajetizotimosixobe.pdfIn PDF document text
    • http://mecateengenharia.com.br/ckfinder/userfiles/files/puvimipulanidanu.pdfIn PDF document text
    • http://ky-auto.com/uploadfile/files/zoxoxe.pdfIn PDF document text
    • https://uaqbakery.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c1d4a3385a6---25453425287.pdfIn PDF document text
    • http://ateliergermain.net/sites/default/files/file/43584904908.pdfIn PDF document text
    • http://www.sparkprototypes.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612030487240c---nilufusepe.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BkSY9tpko7c/uplcv?utm_term=separation+techniques+worksheet+4+answer+keyPDF 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_off0000b594.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB594 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cda6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCDA6 16204 bytes
SHA-256: 68ca033e89656ec15075f9562fe855619b12512790c58f584dcd3e96a983fb4f
font_02_sfnt_off0000f732.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF732 11116 bytes
SHA-256: b60eaedbd0112e93c0f5e685c6588e42834cebfc6855f4826e1b9ac2a7ef1a99

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