Malicious PDF — malware analysis report

Static analysis result for SHA-256 81b49c21598a6a99…

MALICIOUS

PDF

79.1 KB Created: 2021-09-21 00:19:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 7d4ef1e8519f076e5d539711787f85f9 SHA-1: 6b18b4fac9032022f918d3100e0ddb87007863f2 SHA-256: 81b49c21598a6a999bfbe560a2127c4d15ed4a80dda6555139cafc35ac3c39bf
156 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier. It contains numerous embedded URLs, many pointing to compromised WordPress sites and disposable hosting, suggesting a link farm or phishing lure. The `PDF_SEO_DISPOSABLE_LINK_FARM` heuristic indicates a pattern of using disposable hosting for these links, likely to evade detection and promote specific search terms.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9911

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://smidgel.ru/uplcv?utm_term=how+to+install+software+in+android+tablet+from+pc PDF link annotation
    • http://neodev.space/wp-content/plugins/formcraft/file-upload/server/content/files/1613c24719e526---18092981524.pdfIn PDF document text
    • https://xn--90aoja6ahg5ds.xn--p1ai/uploads/files/lapuresasanizexi.pdfIn PDF document text
    • https://www.popcaffe.it/wp-content/plugins/super-forms/uploads/php/files/967e7f045986f5804b4d997d2d47ec3e/52213903499.pdfIn PDF document text
    • http://chroscina.com/userfiles/file/73192002656.pdfIn PDF document text
    • https://signatureshreyas.in/userfiles/file/77312980453.pdfIn PDF document text
    • http://abwva.com/uploads/files/50433399814.pdfIn PDF document text
    • http://www.johnknox.ch/wp-content/plugins/formcraft/file-upload/server/content/files/161334be42bb60---kozitakawubuvopanajif.pdfIn PDF document text
    • http://faurerom.com/userfiles/file/6564604468.pdfIn PDF document text
    • https://penzion-palice.cz/content/bajolawelivopuvujetokogez.pdfIn PDF document text
    • https://houstoncoinclub.org/FCKeditor/file/dadogirebaxugukukakolek.pdfIn PDF document text
    • http://spartaksedlec.cz/spartaksedlec/userfiles/file/zelozegigiwedikufokepinug.pdfIn PDF document text
    • http://mayepnuocmia.vn/data/ckfinder/files/zoxarenadunavovo.pdfIn PDF document text
    • http://signexpowholesale.com/project-new/christianbook/upload_images/file/79377621333.pdfIn PDF document text
    • https://jechrina.gr/FCKeditor/userimages/file/zibemivadalam.pdfIn PDF document text
    • http://lsneotek.com/ckupload/files/84580554627.pdfIn PDF document text
    • http://www.argentum.com/wp-content/plugins/super-forms/uploads/php/files/vsk5rlmm63g6pg0d45p2hvagt8/dosetuvuzo.pdfIn PDF document text
    • https://aquarell.ro/userfiles/file/jifivoweputu.pdfIn PDF document text
    • http://kwiatmetal.pl/userfiles/file/gebunozokulozinigu.pdfIn PDF document text
    • https://sealordhotels.com/ckfinder/userfiles/files/goxivimuxeroleme.pdfIn PDF document text
    • http://4bx.pl/public/file/mojekabakokubasavadadir.pdfIn PDF document text
    • https://natyabio.com/uploadfiles/5037029534.pdfIn PDF document text
    • https://www.harnoordesigns.com/wp-content/plugins/super-forms/uploads/php/files/36283081f6b8a79a20dbf760e1e9c4ef/21155927287.pdfIn PDF document text
    • https://vmwarts.com/ecovic/file/66075717567.pdfIn PDF document text
    • https://brusroom.com/wp-content/plugins/super-forms/uploads/php/files/90a5d054c70811a51e1bace3fd7dfdb5/62529117807.pdfIn PDF document text
    • http://droneducational.com/admin/userfiles/file/lomawo.pdfIn PDF document text
    • http://sabancilojistik.com/userfiles/file/zuwubebirifulugemavinupu.pdfIn PDF document text
    • https://rawoctane.com/uploads/file/54856131269.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_off0000cf7e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCF7E 17712 bytes
SHA-256: 5577fc2d859c50dac7df06e0f870855f568c2caf85dac6a0ec30578785157a3f
font_01_sfnt_off0000fcec.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFCEC 10996 bytes
SHA-256: b3e65ed5658fd699b3ea261c244b7a37b868edcc21cb9cebfa90cb7cd5e55f49
font_02_sfnt_off00011644.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11644 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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