Malicious PDF — malware analysis report

Static analysis result for SHA-256 33ca4b269b5eb941…

MALICIOUS

PDF

81.1 KB Created: 2021-09-17 18:42:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 67a8a638ec3736c0aff75fc7a62c3d7d SHA-1: 739fb779c5394b24d1e30b9de712816e83c3472f SHA-256: 33ca4b269b5eb9419792c425f2c88b5dfdb849d8bc7e4837b3b1959521f999f3
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains numerous embedded URLs that point to various domains, many of which appear to be compromised or disposable hosting. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a pattern of using small PDFs as link farms on disposable hosting, and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' suggests these links are hosted on compromised WordPress sites. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. No scripts were extracted, but the primary attack vector appears to be the embedded URLs leading to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://crewmak.ru/uplcv?utm_term=android+enable+file+transfer PDF link annotation
    • https://jackinthegymtpe.com/uploads/files/202109010229444970.pdfIn PDF document text
    • http://pes.edu.mn/ckfinder/userfiles/files/24578608698.pdfIn PDF document text
    • http://secondhandgraphics.com/usrfiles/file/41626486090.pdfIn PDF document text
    • http://szentdorottyapatika.hu/files/duzobarizukoberup.pdfIn PDF document text
    • https://viajespereira.com/wp-content/plugins/formcraft/file-upload/server/content/files/161449fcae6ae1---42221280691.pdfIn PDF document text
    • https://ensegun2.com/ckfinder/userfiles/files/75468784687.pdfIn PDF document text
    • http://wumag.pl/userfiles/file/mefovegutipenulovunu.pdfIn PDF document text
    • http://www.magicapro.it/wp-content/plugins/formcraft/file-upload/server/content/files/16133f287ef35d---xivigixiri.pdfIn PDF document text
    • http://jockmurray.com/wp-content/plugins/formcraft/file-upload/server/content/files/16141ee5e71d2f---mevomodimorupomup.pdfIn PDF document text
    • https://bleikss.com/userfiles/file/75991802119.pdfIn PDF document text
    • http://www.kickcommerce.com/userfiles/file/misukidosuxu.pdfIn PDF document text
    • http://robfredo.com/userfiles/file/tivesotet.pdfIn PDF document text
    • https://brigitte-farner.ch/userfiles/files/sajaxir.pdfIn PDF document text
    • http://hueide.com/upload/files/87747901952.pdfIn PDF document text
    • https://ccaquebec.com/userupload/files/zatel.pdfIn PDF document text
    • https://ags-car.com/upload/files/tuturuluzotoz.pdfIn PDF document text
    • http://shuimotongyuan.com/userfiles/file/87177430903.pdfIn PDF document text
    • http://saxonrt.hu/img/userfiles/files/46048000832.pdfIn PDF document text
    • https://beldapin.com/calisma2/files/uploads/pigixeduvopiri.pdfIn PDF document text
    • http://kursadowicz.pl/Upload/file/87683169738.pdfIn PDF document text
    • http://kxqcgs.net/filespath/files/20210912205120.pdfIn PDF document text
    • http://zsdbiopharm.com/upload/files/23981715128.pdfIn PDF document text
    • http://www.afurg.com.br/assets/ckfinder/userfiles/files/96809202239.pdfIn PDF document text
    • http://ahchala.com/img/file/26254854682.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_off0000d597.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD597 19100 bytes
SHA-256: 95cfaf0a7a71cf1e4050e238f23b7e7c3b3c99c419450dc8de485ddb01df4797
font_01_sfnt_off000106a1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x106A1 10468 bytes
SHA-256: b5154d531aa9c6c9322bfe542eb68ea08c3e21e238cc187be96b2d8464d58b11
font_02_sfnt_off00011e85.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E85 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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