Malicious PDF — malware analysis report

Static analysis result for SHA-256 bb71ae112f980713…

MALICIOUS

PDF

80.8 KB Created: 2021-09-05 11:34:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: cf06c97e59459e07e021fb82d4b359a2 SHA-1: 5c16d7ab74b52be5f862d792a3380b277694bb5a SHA-256: bb71ae112f9807137ed3a036cd5f3aacea2c570b6c1896215ec37551bb4b43d9
156 Risk Score

Malware Insights

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

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many of which point to compromised WordPress sites or disposable hosting, suggesting a link farm designed to redirect users to malicious content. The document body is heavily obfuscated and appears to be metadata from the wkhtmltopdf tool rather than user-readable content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://synerhu.ru/uplcv?utm_term=branding+identity+guidelines+pdf PDF link annotation
    • https://cafesca.info/ckfinder/userfiles/files/tupikewasogodike.pdfIn PDF document text
    • https://maychieuvinh.vn/upload/files/34663931923.pdfIn PDF document text
    • http://spiregene.com/image/files/20210810_112740.pdfIn PDF document text
    • http://nriloan.jctoursandtravels.in/files/96786991435.pdfIn PDF document text
    • https://iphonerepairservice.nl/app/webroot/files/userfiles/files/59752823949.pdfIn PDF document text
    • http://maynenkhiinverter.com/media/ftp/file/77660037942.pdfIn PDF document text
    • https://luxurytravel-show.com/wp-content/plugins/super-forms/uploads/php/files/69879befc6c39f7601625e8ea43dcaba/xalewomodudenipedadoga.pdfIn PDF document text
    • http://adanateknikservis.web.tr/wp-content/plugins/formcraft/file-upload/server/content/files/1607887b7e0278---valumosawi.pdfIn PDF document text
    • http://gapp.fr/medias/files/revesadezomofesukupimi.pdfIn PDF document text
    • http://trunglam.vn/uploads/userfiles/file/ditex.pdfIn PDF document text
    • http://randygordonlawoffice.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/61669358501.pdfIn PDF document text
    • http://centrumbiznesurawicz.pl/userfiles/file/34636016549.pdfIn PDF document text
    • http://club-integra.ru/userfiles/file/24793157355.pdfIn PDF document text
    • https://pensiuneavalentina.ro/app/webroot/file/juxirinedotaxojeze.pdfIn PDF document text
    • https://www.fifatravels.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e977d07491a---12505069946.pdfIn PDF document text
    • https://realimpacto.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160b9b12dcc790---50138090784.pdfIn PDF document text
    • http://adanateknikservis.web.tr/wp-content/plugins/formcraft/file-upload/server/content/files/16078d394d533a---mofiloje.pdfIn PDF document text
    • https://gresathouse.com/wp-content/plugins/super-forms/uploads/php/files/9aab64b8f5b93e05558bab8fd5a97fc8/29395144824.pdfIn PDF document text
    • http://frederickfollows.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160e30e63b7ec8---1455221845.pdfIn PDF document text
    • http://kimhoatra.vn/upload/fckimagesfile/49187039393.pdfIn PDF document text
    • https://ural-aiti.ru/admin/ckfinder/userfiles/files/fadofageta.pdfIn PDF document text
    • http://www.firengo.com/userfiles/files/pexesizuxafutimopufofob.pdfIn PDF document text
    • https://www.karenlovelee.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bfd19b5a933---farikapaz.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_off0000d84d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD84D 17036 bytes
SHA-256: ee27166382d8861c3366b6545cd9482c90585c3771f9baa7142a449619c4b821
font_01_sfnt_off0001046d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1046D 10820 bytes
SHA-256: ad119efb14878ac332550e48f7544efc198c199210a6428b945b4e1055b00123
font_02_sfnt_off00011d52.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11D52 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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