Malicious PDF — malware analysis report

Static analysis result for SHA-256 51395b9c0c0ae4d4…

MALICIOUS

PDF

81.4 KB Created: 2021-09-02 16:45:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 40d19a9cd0d0e6ce96bd701fb34d64f3 SHA-1: f0d39c0f5406aa24d9ca3c6351d132046477d457 SHA-256: 51395b9c0c0ae4d415abcbbe9d17e0fe2d34ff6e3bad22431dd67ad00712fd96
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as malicious by ClamAV and an ML classifier, exhibiting characteristics of a phishing or malware distribution lure. It contains numerous links to external URLs, many hosted on compromised WordPress sites or disposable domains, suggesting an attempt to redirect users to malicious content. The presence of PDF_RANDOM_URL_LINK and PDF_SEO_DISPOSABLE_LINK_FARM heuristics further supports this, indicating a pattern of linking to potentially harmful or deceptive sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 7

  • 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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://huntic.ru/uplcv?utm_term=surface+area+and+volume+of+cuboids+worksheet PDF link annotation
    • http://www.morrisjones.co.uk/EditorImages/file/rafisarevenutopepone.pdfIn PDF document text
    • http://fotografiafrancescosomma.com/userfiles/files/sigerimusaxafum.pdfIn PDF document text
    • https://getlovebooks.com/wp-content/plugins/super-forms/uploads/php/files/aba09e976491817fe81938ae83a68531/77913525583.pdfIn PDF document text
    • https://open-call.fr/uploaded/files/38119532979.pdfIn PDF document text
    • http://gymostrov.org/gymostrov/userfiles/file/21974403294.pdfIn PDF document text
    • https://sanidom.pl/img/file/walunepo.pdfIn PDF document text
    • http://www.ncstarim.com.tr/wp-content/plugins/super-forms/uploads/php/files/lan7lrrjbhd10nlolmbha97800/70076461703.pdfIn PDF document text
    • http://faradtvandor.hu/picture/userfiles/file/49077233873.pdfIn PDF document text
    • https://socialacademy.gr/wp-content/plugins/super-forms/uploads/php/files/a134719acaa5b8ddf6a34fec4ce19aa4/zelowuwinojekeduni.pdfIn PDF document text
    • https://rsun.pro/admin/ckfinder/userfiles/files/90823008147.pdfIn PDF document text
    • https://www.ciabrini-immobilier.com/wp-content/plugins/super-forms/uploads/php/files/osa430iu2mm1k6koliedukfc1e/derujinimupelarivolodoman.pdfIn PDF document text
    • https://completecollegestrategies.com/wp-content/plugins/super-forms/uploads/php/files/47b38c65ee1bdc20be968683e5dd49b4/64695441568.pdfIn PDF document text
    • https://www.inkfactory.pk/wp-content/plugins/formcraft/file-upload/server/content/files/160739f9066e36---41959360024.pdfIn PDF document text
    • https://wacee.net/wp-content/plugins/formcraft/file-upload/server/content/files/161266c1f28d2d---ravebidinevuvowumuta.pdfIn PDF document text
    • http://circuitoinsulargc.com/documentos/file/58594699365.pdfIn PDF document text
    • http://cphs1970.net/clients/877309/File/gunagisisejazojepamunorud.pdfIn PDF document text
    • https://internationallanguagenavigators.com/media/vexinazim.pdfIn PDF document text
    • https://lanegarrett.net/userfiles/file/91269433983.pdfIn PDF document text
    • http://counterreaction.net/wp-content/plugins/formcraft/file-upload/server/content/files/160bd9fdf12a4b---588401414.pdfIn PDF document text
    • https://bonafideonline.com.ar/wp-content/plugins/super-forms/uploads/php/files/8fb979bc933deb53dd7a9ec84caa9c9a/76573624123.pdfIn PDF document text
    • 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_off0000d82f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD82F 11300 bytes
SHA-256: a00125a0c2716e11f8344a9c3fa6684dbb1ab139715c4a1a60b59c111d71c1f4
font_01_sfnt_off0000f294.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF294 17496 bytes
SHA-256: a7738499227278e940a5566a6021f56fd0d2d6d5d7d32a27302b22d7d278c570
font_02_sfnt_off00011fa7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11FA7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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