Malicious PDF — malware analysis report

Static analysis result for SHA-256 4cf31a8a421523ca…

MALICIOUS

PDF

83.8 KB Created: 2021-09-06 18:24:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: 6aa30a7b19134ec25f0793c74fe6bbe5 SHA-1: 2ba3981cd0c8cdf071837568cd5efaf91fd9f290 SHA-256: 4cf31a8a421523cad968f567186c18a1a9233569148cd9e9fe72a012371bf904
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF was flagged by ClamAV as Pdf.Phishing.Trojan and an ML classifier indicated a high probability of maliciousness. It contains numerous embedded URLs, many pointing to compromised CMS uploads and disposable hosting, suggesting a phishing or redirection attempt. While no scripts were explicitly extracted, the PDF structure and URL patterns are indicative of a phishing lure, likely delivered as a spearphishing attachment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9860

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://marciasmithconsulting.com/wp-content/plugins/super-forms/uploads/php/files/d35a2be774a1cda01ecceafa1406cafb/vukol.pdf In PDF document text
    • https://stockbauer.hu/uploads/file/40079559580.pdfIn PDF document text
    • https://vetranhtuongmamnon.vn/wp-content/plugins/super-forms/uploads/php/files/ngpujhm25vhhqa1ul7uvmegtj8/kizeperimaz.pdfIn PDF document text
    • https://remoteworkerclub.com/wp-content/plugins/super-forms/uploads/php/files/4ddccf331e6a8bf664e3f34acb7ef16b/pezojumadifatasilezepo.pdfIn PDF document text
    • http://www.psstrecno.sk/wp-content/plugins/formcraft/file-upload/server/content/files/160c24d80ce742---wugadugukusilodepep.pdfIn PDF document text
    • http://lakshimi-kaatsu.com/user_data/packages/default/imgfiles/rusiwagos.pdfIn PDF document text
    • http://ottotech.center/userfiles/file/wenufafeto.pdfIn PDF document text
    • https://agsposure.org/wp-content/plugins/super-forms/uploads/php/files/4e66edd1207f70a359c0e5a27b531c37/6256744193.pdfIn PDF document text
    • http://relatives-united.com/clients/75139/File/xikitalubawo.pdfIn PDF document text
    • https://novzelandiya.ru/ckfinder/userfiles/files/xadazukurojukesadogaba.pdfIn PDF document text
    • http://abwingscolley.com/uploads/files/vurefewifo.pdfIn PDF document text
    • http://hasici-pristroje-eshop.cz/files/file/23866240805.pdfIn PDF document text
    • https://nhathuydesign.com/wp-content/plugins/super-forms/uploads/php/files/qidm2mrrugi4m5umcnua33005i/48955451434.pdfIn PDF document text
    • https://sabagdasarov.ru/upload/file/56378099060.pdfIn PDF document text
    • http://beetsom.com/PROGRAM_FCKeditor_UserFiles/file/187214097260bed30975e58.pdfIn PDF document text
    • https://tagoproperties.com/ckfinder/userfiles/files/49890671758.pdfIn PDF document text
    • http://carnavaldemarbella.com/Senegal_5/Content/files/userfiles/file/10078074265.pdfIn PDF document text
    • http://www.vitrierbxl.be/wp-content/plugins/formcraft/file-upload/server/content/files/16077ccc8e6e8e---fodeloguvid.pdfIn PDF document text
    • http://recamonde.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160895a99cf93e---13190505143.pdfIn PDF document text
    • https://www.capitalroofingct.com/wp-content/plugins/formcraft/file-upload/server/content/files/1610e184c47746---34898425202.pdfIn PDF document text
    • https://manuscripthandler.com/userfiles/file/79604301484.pdfIn PDF document text
    • http://longarmacademy.net/fckeditor/userfiles/file/niravokifomeputevefo.pdfIn PDF document text
    • https://rainbowfurnitures.com/files/files/50187979477.pdfIn PDF document text
    • http://anatolianlgs.com/userfiles/file/dosuxatuvazovipuxo.pdfIn PDF document text
    • https://allianceflooring.net/wp-content/plugins/super-forms/uploads/php/files/adf398e6fe08988c836cf497d13a2f0b/81398963230.pdfIn PDF document text
    • http://gsoam.ge/wp-content/plugins/formcraft/file-upload/server/content/files/16083331b29816---xajifitob.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3vuEKuznOb8/uplcv?utm_term=indicadores+de+calidad+de+enfermeria+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_off0000e142.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE142 19120 bytes
SHA-256: 612eb160a024841a3bbee6722b9c274ec46a684f6dcbd3084924f44eead38f16
font_01_sfnt_off0001111b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1111B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012932.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12932 10636 bytes
SHA-256: a78b986d554968496b47707086b442979c40069053c6c40bee06b9cefbaf4169

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