Malicious PDF — malware analysis report

Static analysis result for SHA-256 cdba928da9944e01…

MALICIOUS

PDF

82.2 KB Created: 2021-09-01 05:55:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 9511f8c86652765df199344916c3bdd8 SHA-1: 4be8a40b05b0e9a38d4ca41b98751cd277ae9760 SHA-256: cdba928da9944e0196bcd8b5e1ae3ab26280164d95174f2bb314103dc50eee6f
156 Risk Score

Malware Insights

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

The file was identified as malicious by ML classifiers and ClamAV, specifically as a phishing trojan. Static analysis revealed it functions as a link farm, with numerous URLs pointing to external sites, including those hosted on compromised WordPress installations. The document body is heavily obfuscated and appears to be auto-generated content from wkhtmltopdf, providing no user-facing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

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 https://djecijagarderoba.me/userfiles/file/zotubisejuxowefuli.pdf In PDF document text
    • http://kleni.cz/userfiles/file/41937247811.pdfIn PDF document text
    • http://conservationenergy.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608248465ec47---wenotifofuradezukoz.pdfIn PDF document text
    • https://bamfieldrental.com/userfiles/file/fejagefaripofotad.pdfIn PDF document text
    • http://www.holzbau-hoelzl.at/wp-content/plugins/formcraft/file-upload/server/content/files/1611aecdc99f15---manigu.pdfIn PDF document text
    • http://analogsys.com/uploaded/file/14561691296090ad0209c62.pdfIn PDF document text
    • http://www.saraviation.com/wp-content/plugins/formcraft/file-upload/server/content/files/16087cd2431a37---74210232162.pdfIn PDF document text
    • https://wanfutemple.urwaydesign.com/data/file/userfiles/files/boxakenowarokolex.pdfIn PDF document text
    • http://jeugdopdewetenschapsagenda.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160df8b8a5796e---vejoreburosotuzopu.pdfIn PDF document text
    • http://jandenzobv.com/image_uploads/file/60455282854.pdfIn PDF document text
    • http://artpolyclinic.com/file/files/80429981561.pdfIn PDF document text
    • http://www.iycadana.org/wp-content/plugins/super-forms/uploads/php/files/rv4309e6j0bj7qishjjt7mrub3/68836470790.pdfIn PDF document text
    • http://daehwa.info/uploaded/file/92501636032.pdfIn PDF document text
    • https://agrotehholding.ru/wp-content/plugins/super-forms/uploads/php/files/04296e55fe0dae99afb29f8a211742cb/diposaxijijobis.pdfIn PDF document text
    • https://magazinul-de-instalatii-sanitare.ro/app/webroot/files/userfiles/files/zububufufevezo.pdfIn PDF document text
    • https://member-amz-seller-system.de/wp-content/plugins/super-forms/uploads/php/files/6bec4551be54fe796139fbcf79329817/86702265358.pdfIn PDF document text
    • https://ajitcoatings.com/uploads/23256232966.pdfIn PDF document text
    • http://principessavencanice.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a33c6b4d19a---jivuzalazuwuzomesax.pdfIn PDF document text
    • https://relaxbotanika.cz/ckfinder/userfiles/files/49663000200.pdfIn PDF document text
    • http://wenxuezj.com/images/File/rirewovamikixevegilo.pdfIn PDF document text
    • https://sandalyecenneti.com/wp-content/plugins/super-forms/uploads/php/files/7funnf0cmtesaf8f8nlh17re91/94634655828.pdfIn PDF document text
    • https://uaqbakery.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609e870eafcbc---kunofi.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/6naE_Nh8_CY/uplcv?utm_term=cooking+back+ribsPDF 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_off0000dd92.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD92 17520 bytes
SHA-256: 600a9265b8e7c14574a1f4ae9c50166d2d28b20e16d6e877b8f25bb000fb97d4
font_01_sfnt_off00010ac3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10AC3 10392 bytes
SHA-256: 987708a3082df1141e0819d992666583ecfab1b08622af09c4cbb7ee76d98248
font_02_sfnt_off00012276.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12276 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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