Malicious PDF — malware analysis report

Static analysis result for SHA-256 31bd21d5d236b888…

MALICIOUS

PDF

63.6 KB Created: 2021-10-11 14:37:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-20
MD5: 229b9331617cf4d6c9a0c0658f1dd539 SHA-1: 4e8234a22f4844a374a663a48cb92f1d2f037636 SHA-256: 31bd21d5d236b88869d81af6d4e832dfd56f3bec8e498bbb4be059b65b8a5869
154 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a link farm pointing to multiple disposable domains and compromised CMS upload storage, indicating a phishing or malware distribution attempt. ClamAV detected this file as 'Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0', and ML classifiers also flagged it as malicious. The document body is heavily obfuscated and unreadable, but the presence of numerous external links suggests malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.8948

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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
  • 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://ddriu.hu/wp-content/plugins/super-forms/uploads/php/files/e3e8ac9e757507d686ff1ba104400ea4/27319581054.pdf In PDF document text
    • http://xn--o39a91gvwm83kbsn.com/FileData/ckfinder/files/20210907_63AD19F99DECC01C.pdfIn PDF document text
    • https://robert-zauer.cz/userfiles/file/daxupixozabawatarugufe.pdfIn PDF document text
    • https://swagath.co/new/ckfinder/userfiles/files/22262610127.pdfIn PDF document text
    • https://akilanews.com/ckfinder/userfiles/files/rilaxigavafejimatotibixe.pdfIn PDF document text
    • https://altstudio.be/app/webroot/uploads/file/ginolurajozimapavemus.pdfIn PDF document text
    • https://juhaszautovill.hu/userfiles/file/1608937827.pdfIn PDF document text
    • http://hzosm.com/images/upload/File/41066433786.pdfIn PDF document text
    • https://indobaliart.com/sitefiles/file/64402807207.pdfIn PDF document text
    • https://eko-briketes.lv/userfiles/files/34911803886.pdfIn PDF document text
    • http://heimundsicherheit.de/userfiles/file/dipopawurobopexubazajaxa.pdfIn PDF document text
    • http://explosivedevices.ru/media/file/wexojipapojex.pdfIn PDF document text
    • http://chiari-web.com/ckfinder/optimist/files/46039766713.pdfIn PDF document text
    • https://growmytruck.com/wp-content/plugins/super-forms/uploads/php/files/4c1afb935b2948d6493016874a5077ab/5718421447.pdfIn PDF document text
    • https://tonere.shop/app/webroot/files/userfiles/files/28010050032.pdfIn PDF document text
    • http://olympiad-bigben.ru/ckfinder/userfiles/files/jogewiwutovuzumaxasamagi.pdfIn PDF document text
    • https://fotobolfestmeny.hu/mvc/userfiles/file/ronavaza.pdfIn PDF document text
    • http://domesticsolutionsagency.com/userfiles/file/nediwuza.pdfIn PDF document text
    • https://selectwifi.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613680c037c10---24693517829.pdfIn PDF document text
    • http://24x7taazasamachar.com/assets/ckfinder/core/connector/php/uploads/files/lowetipexujobokako.pdfIn PDF document text
    • http://moonlightmontessori.com/upload/files/patipi.pdfIn PDF document text
    • http://ueros.fr/admin/ckfinder/userfiles/files/47814999338.pdfIn PDF document text
    • http://feedproxy.google.com/~r/Xvkpad/~3/2I9n2o-U8HI/uplcv?utm_term=i+remember+you+hello+monsterPDF link annotation
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000df1f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF1F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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