Malicious PDF — malware analysis report

Static analysis result for SHA-256 8fe55a1b2cdc0914…

MALICIOUS

PDF

97.8 KB Created: 2021-07-20 17:52:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: a4e979d5e34cdbd4459aca6ceab94603 SHA-1: 906b494b70e42ded2d0aac5a91e89e4da88e7eca SHA-256: 8fe55a1b2cdc09148f8f798844b6f5e6d97aabc0d680ece630e42552b3a5ac8a
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous links, many pointing to compromised CMS upload directories, indicating a link farm designed to distribute malicious content or phish users. The ML classifier and ClamAV detection strongly support its malicious nature. 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 0.9928

Heuristics 6

  • 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
  • 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://originalcheck.it/public/img_admin/file///fatorevipitizegebunokap.pdf
    • http://www.pirac.org/wp-content/plugins/super-forms/uploads/php/files/49df30a0eea796edb54570167039d741/foperanaziniper.pdf
    • https://vmkstroi.ru/wp-content/plugins/super-forms/uploads/php/files/8717294443aecd7cca910fe85b6e0380/40451345176.pdf
    • http://tgtech-auto.com/userfiles/file/89546936961.pdf
    • http://okmarin.ru/userfiles/file/67102584736.pdf
    • http://bubblesoflove.net/wp-content/plugins/formcraft/file-upload/server/content/files/160beabb7812fa---20188209202.pdf
    • http://www.jesuseslaroca.org/wp-content/plugins/formcraft/file-upload/server/content/files/1609dbce320173---nejorajatomasoxojonamowe.pdf
    • http://www.dadosefatos.net.br/wp-content/plugins/formcraft/file-upload/server/content/files/1609f532a60799---78705078155.pdf
    • http://1970fchs50thclassreunion.com/clients/1/19/19770213778af891f1b13fa25f964f50/File/ketazudapotefedu.pdf
    • https://thewaves.net/wp-content/plugins/super-forms/uploads/php/files/hjtbssvmtbbs0bh759dclu50mn/jikafaxoxoxegixekovalek.pdf
    • http://bsl-trans.ru/admin/ckfinder/userfiles/files/9826271070.pdf
    • https://anthonygillant.com/userfiles/file/16564239903.pdf
    • http://paymentsbusiness.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160a4f020e2f98---61788745069.pdf
    • https://ventana-sur.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e648e68ba9b.pdf
    • https://www.plsok.com/wp-content/plugins/super-forms/uploads/php/files/874dc5286d680c599cfa3f736994ac05/zijolinuv.pdf
    • https://starbox.fr/img/files/7306377642.pdf
    • https://erinmillssmilesdentistry.com/wp-content/plugins/super-forms/uploads/php/files/uqtot0jikll5r2156i7flllr24/27883978625.pdf
    • https://amkboiler.com/wp-content/plugins/super-forms/uploads/php/files/7nv90fsq050831n8v2i7tmb43b/rubiniwibavuvavuka.pdf
    • http://www.nbrownies.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160ad46d97101f---62110076611.pdf
    • http://narnivet.com/userfiles/files/nukazenizav.pdf
    • https://www.baileysmilk.com/wp-content/plugins/super-forms/uploads/php/files/4af2ec9dc4ca70e1cd9bdf0d4c659e31/gosokazeg.pdf
    • http://bpabv.nl/uploadfiles/file/gatetaga.pdf
    • http://www.kreasoft.mx/wp-content/plugins/formcraft/file-upload/server/content/files/160bf90e2dacd6---6671925945.pdf
    • https://www.caesarstravel.com/wp-content/plugins/formcraft/file-upload/server/content/files/16093b01e7c137---9032688799.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1KS0DP0cxss/uplcv?utm_term=game+of+thrones+main+theme+piano+sheet
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00011976.bin
b1ef8c1684b5ff2de4217bf99d2acea667382b1fd5fbda04e210f0e9a0f711c8
pdf-font-stream PDF embedded font (sfnt) at offset 0x11976 10616 bytes
font_01_sfnt_off00013194.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x13194 16792 bytes
font_02_sfnt_off000149a6.bin
f8893588690e38320794450904d731ff60489ed9067f447b2c91b277cb5549aa
pdf-font-stream PDF embedded font (sfnt) at offset 0x149A6 18344 bytes