Malicious PDF — malware analysis report

Static analysis result for SHA-256 6f5f9566e048c03b…

MALICIOUS

PDF

70.8 KB Created: 2021-09-02 16:33:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 332e42d0168fe71420a9512aed5b6f12 SHA-1: aa20a641839cc27cf06a47dd56374e169a4ec0fc SHA-256: 6f5f9566e048c03bdf3efd9107f57d4ea026ccaa35cccd8340c1167d25921a8b
156 Risk Score

Malware Insights

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

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and an ML classifier indicated a high probability of maliciousness. It contains numerous embedded URLs, many of which point to compromised CMS uploads or disposable hosting, suggesting a link farm designed to redirect users. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, further obscuring its true intent beyond the link farm heuristic.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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://sdyh.gr/wp-content/plugins/super-forms/uploads/php/files/1fg7l91e1ujh1ienqrq40ncqq3/49630720322.pdf In PDF document text
    • http://kroonzuivel.nl/ckfinder/userfiles/files/nogawidogusumawid.pdfIn PDF document text
    • http://www.pirac.org/wp-content/plugins/super-forms/uploads/php/files/9d71d42f574f626508892b0716f9fa4c/17376384564.pdfIn PDF document text
    • http://huspanda.com/data/ckfinder/files/78056578772.pdfIn PDF document text
    • http://kasargod.net/uploads/file/23179361554.pdfIn PDF document text
    • http://grafordexstudents.com/clients/0/05/05b3dbe7dd9dc6f92b523d2b721f2ffd/File/83913975122.pdfIn PDF document text
    • http://neuragen.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160d08e0fbfeda---80857381649.pdfIn PDF document text
    • https://jackyrouxmethode.com/userfiles/file/48216927309.pdfIn PDF document text
    • https://abandassociates.com/ckfinder/userfiles/files/53246311196.pdfIn PDF document text
    • http://premiumresourcing.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c0c79359af0---dujisoxugiweniwexu.pdfIn PDF document text
    • http://klasykarozrywki.pl/public/images/fck/file/24659845703.pdfIn PDF document text
    • http://perles-del-beya.com/userfiles/file/zepivejolage.pdfIn PDF document text
    • https://petroblend.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c89a214d6d1---18711718585.pdfIn PDF document text
    • http://onsijsselstein.nl/userfiles/files/balutefareruxaxev.pdfIn PDF document text
    • http://wisdomtours.net/upload/file/zofugadudukodave.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b0cfd11dc5b---13442569115.pdfIn PDF document text
    • http://ombs.ru/uploads/files/ligipatimasimaker.pdfIn PDF document text
    • http://zimaletto.com/uploads/file/bipesexuvaxivoxuna.pdfIn PDF document text
    • https://fellowpeo.com/wp-content/plugins/super-forms/uploads/php/files/bd7db8a0aaed3efdc2224f949cec1068/18789219693.pdfIn PDF document text
    • http://agriturismocorteerbatici.it/userfiles/files/xezuz.pdfIn PDF document text
    • http://www.nowsingapore.co.id/wp-content/plugins/formcraft/file-upload/server/content/files/1608e4afca4861---48156929731.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/fzgW7-mxBc0/uplcv?utm_term=hip+mobility+band+exercises+pdfPDF 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_off0000b426.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB426 15760 bytes
SHA-256: 59da31ab5e5bb0b8a7a18c228af14cf6b3bea3b49aa47d8db2c4fef669297890
font_01_sfnt_off0000dc31.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC31 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f448.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF448 11128 bytes
SHA-256: e6a58e98ca3a0ebe8e5e4b980f977c2a91699a269847717f0af370a6084611b9

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