Malicious PDF — malware analysis report

Static analysis result for SHA-256 4b8dc549b6127c34…

MALICIOUS

PDF

73.3 KB Created: 2021-09-27 08:10:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 6604bf4d7e7d6fc6f96977a9797b7898 SHA-1: 45bd1ba49dd1529b580d9ef56b7bf790e93c3bbf SHA-256: 4b8dc549b6127c34fe98fb284ef045e8a8e3246dc250b505998f2ffff50950d5
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs pointing to external PDF files, indicating a link farm designed to redirect users. Heuristics suggest these links are hosted on compromised CMS uploads and disposable domains, a common tactic for phishing or malware distribution. The ML classifier and ClamAV detection strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

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://inwebjor.ru/uplcv?utm_term=balance+game+download+for+pc+windows+7
    • http://www.pilartangguh.com/file/latoluladumal.pdf
    • https://ra7a7p-h3ba7.com/contents/files/foluk.pdf
    • https://gruppopolidori.com/upload/image/file/88739612631.pdf
    • http://medtravel.lv/images/hand_uploaded/files/17677647316.pdf
    • http://taociren.com/upload/file/210922105040466501vd5xbyn2l5n9.pdf
    • https://pamukoglu.com/userfiles/file/gewebizadevo.pdf
    • http://silverk.ru/img/lib/file/roxel.pdf
    • http://www.bc-arman.kz/ckfinder/userfiles/files/62916689071.pdf
    • https://full-e.com/app/webroot/userfiles/files/20210916_060338.pdf
    • http://designbeginnings.com/upload/file/70992499080.pdf
    • https://pilot-nav.socksnbows.com/ckfinder/userfiles/files/7789484942.pdf
    • http://prodesign31.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16146b9bb8a7d5---nujuxefo.pdf
    • http://matras-devison.ru/upload/file/36199241253.pdf
    • http://back2wood.de/userfiles/file/favudibitazuvapazaxug.pdf
    • https://icbacademy.com/upload/files/54853863940.pdf
    • http://vandofigueiredo.com/userfiles/file///23967415582.pdf
    • https://yournew.site/wp-content/plugins/super-forms/uploads/php/files/3tlmlem644lmus37c6s08q5hpn/xelapivojimifupozevozari.pdf
    • http://videoacceso.com/wp-content/plugins/formcraft/file-upload/server/content/files/16140e70e9cb54---68062093675.pdf
    • https://www.soroptimist.be/oldsite/intranet/ckeditor/ckfinder/userfiles/images/files/37311048591.pdf
    • https://yenhuy.vn/upload/files/66823470448.pdf
    • http://stepasidemedical.com/images/uploads/file/28674431319.pdf
    • http://newo.ru/files/files/83327897655.pdf
    • http://turnyras.lt/Files/file/64442171082.pdf
    • 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_off0000b283.bin
25903098c4979bd4162c0fcf7d58e19c04aaf93fd34ea8af16c422dc07557a42		 pdf-font-stream PDF embedded font (sfnt) at offset 0xB283 19784 bytes
font_01_sfnt_off0000e5cb.bin
8e98543b0e3016758d7f80f1761d60abcb9e2b634d2b1ecdeba430c79655d743		 pdf-font-stream PDF embedded font (sfnt) at offset 0xE5CB 11052 bytes
font_02_sfnt_off0000ff6e.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xFF6E 16792 bytes

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