Malicious PDF — malware analysis report

Static analysis result for SHA-256 c9c4f4b9407f1da4…

MALICIOUS

PDF

71.1 KB Created: 2021-09-08 10:45:03 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: b545b675296bd9e0d1869966e6d91512 SHA-1: 4be40c6991f388438e3a02608b57192281417e29 SHA-256: c9c4f4b9407f1da420dcb96d8c9eaf4a0871f02609f4596eb69533936cfed859
156 Risk Score

Malware Insights

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

The sample is a PDF file identified as malicious by ClamAV and an ML classifier. It contains numerous embedded URLs that point to compromised websites, suggesting it functions as a link farm to distribute malicious content or facilitate phishing. The heuristics indicate a pattern of link farming on disposable hosting and compromised CMS uploads, reinforcing the malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9849

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=antenna+introduction+pdf PDF link annotation
    • https://best-turbos.com/wp-content/plugins/super-forms/uploads/php/files/7c903ba119252579845f8e46affac23e/xapuwofaxafi.pdfIn PDF document text
    • https://greyquotient.com/wp-content/plugins/super-forms/uploads/php/files/9a936c1379a0d51b884998907bb2cbba/jabujuwererupomilifigi.pdfIn PDF document text
    • https://www.hdcorp.com.br/wp-content/plugins/super-forms/uploads/php/files/iitsqh8cbtjqp88vfg2jcdk9m8/sutigisikevisonifisepozup.pdfIn PDF document text
    • https://canevastoilestjean.com/upload/editor/file/pibogekumimenibojajixaniz.pdfIn PDF document text
    • http://www.ssc-ras.ru/ckfinder/userfiles/files/38922803358.pdfIn PDF document text
    • https://rrvchefs.com/wp-content/plugins/super-forms/uploads/php/files/d4d70d66b43b670489de51ac76a64f3a/sarupakido.pdfIn PDF document text
    • http://zadonskiy.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16094badd4bbe7---taloxuno.pdfIn PDF document text
    • http://globalroomplus.com/bot/ckfinder/uf/files/58977816981.pdfIn PDF document text
    • https://mavismanagement.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e675baa52e5---11758570002.pdfIn PDF document text
    • http://k1a.ru/images/files/file/57060683786.pdfIn PDF document text
    • http://clinicaveterinariabilancino.it/userfiles/files/momor.pdfIn PDF document text
    • https://frasertechno.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607893f522902---87299924890.pdfIn PDF document text
    • https://topupdana.com/contents//files/witawije.pdfIn PDF document text
    • https://binarbaidequipment.com/public_html/userfiles/file/92298631616.pdfIn PDF document text
    • http://palyavalaszto.hu/teszt/upload/file/niwumiju.pdfIn PDF document text
    • http://www.majorisinvestimentos.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1607ef335b09bb---2483054940.pdfIn PDF document text
    • https://hoakhanh.vn/uploads/image/files/zaponiru.pdfIn PDF document text
    • https://grand-forge.ru/wp-content/plugins/super-forms/uploads/php/files/02179e7a20a22065f30a4fa3efd1c38f/97739111283.pdfIn PDF document text
    • http://www.siscard.com/wp-content/plugins/formcraft/file-upload/server/content/files/160814f471ef7c---zemuwalivasarejize.pdfIn PDF document text
    • http://raegcafe.com/uploads/files/wibutanarerewidipo.pdfIn PDF document text
    • https://www.cukoyem.com.tr/wp-content/plugins/super-forms/uploads/php/files/oubhlbmhulqnjdglh9j543ngu4/8768867808.pdfIn PDF document text
    • http://festivaldeliteraturadepereira.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608cd2438b81c---57610744624.pdfIn PDF document text
    • https://capecoralliving.com/media/file/fasuzakigaselopis.pdfIn PDF document text
    • http://nail-free.com/ckfinder/userfiles/files/vorokilinipuzivilewarad.pdfIn PDF document text
    • https://jnnjhansi.com/userfiles/file/tinukubuguka.pdfIn PDF document text
    • http://www.ochoadentalcare.com/tacgestorcontenidos_ochoa/documentos/file/midutazifuribezefezonajuw.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_off0000bab4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBAB4 14500 bytes
SHA-256: 4d4bad1cf5c2be8b7a01c765de9f1b55ca637a2a3c30e9007249810a6f36c799
font_01_sfnt_off0000dee6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDEE6 10480 bytes
SHA-256: b35829da07f7be95fa22d39fa53164db056960a02e24553637c785f6c66f7bcf
font_02_sfnt_off0000f6dc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6DC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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