Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef8b6e0a7673c4c9…

MALICIOUS

PDF

92.0 KB Created: 2021-09-02 00:31:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 1a1692fd36ad1e60a84fd19fd99a3f19 SHA-1: ed2865b8f4f84d97b53f58a0e99ab2bcc2f57fc9 SHA-256: ef8b6e0a7673c4c961ad430c5ae6ea323ad8f6d6a9eb4d4e46823fd23775f54e
156 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics as a link farm, with many URLs pointing to potentially compromised websites or disposable hosting. The ML classifier and ClamAV also identified it as malicious, specifically a phishing or trojan variant. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for human readability but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

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 http://3bbb.fr/ckeditor/upload/files/kuzagojerimubojapobofus.pdf In PDF document text
    • http://vietthanhstone.com/images/news/file/budotebalunazetufuse.pdfIn PDF document text
    • http://albatrossmrn.com/konadnew/userfiles/file/zinotunukiwanomukekuxi.pdfIn PDF document text
    • http://agcslohian.com/userfiles/file/godadamut.pdfIn PDF document text
    • https://megatex.ua/images/uploads/file/95517403102.pdfIn PDF document text
    • https://www.elektrobetrieb-scholz.de/wp-content/plugins/formcraft/file-upload/server/content/files/161205fe69c17f---gagabusoz.pdfIn PDF document text
    • https://alfa-clining.ru/wp-content/plugins/super-forms/uploads/php/files/537130e826b924af2b9e2268765f676d/13586299786.pdfIn PDF document text
    • https://turismopontevedra.com/ckfinder/userfiles/files/90255875696.pdfIn PDF document text
    • https://letstravelforacause.com/miet/assets/files/biwidado.pdfIn PDF document text
    • https://kolodezrus.ru/wp-content/plugins/super-forms/uploads/php/files/fbcdf186210dc6f55222747992ce7ca4/zaxiwufagibimojikiw.pdfIn PDF document text
    • http://www.alex-vasilkov.ru/images/wisdom/file/95771611499.pdfIn PDF document text
    • http://edumedcare.pl/upload/files/31672612988.pdfIn PDF document text
    • http://thaoduocvn.com/userfiles/image/file/33990122451.pdfIn PDF document text
    • http://www.drivingschool-brno.cz/files/files/25095970534.pdfIn PDF document text
    • http://bangdinhphucat.com/quangbasanpham/app/webroot/upload/image/files/55154758643.pdfIn PDF document text
    • http://xn----8sbpvg0afdbe.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/t1265fhil199aa4tf9l6710ci6/jerig.pdfIn PDF document text
    • https://dermo.com/wp-content/plugins/formcraft/file-upload/server/content/files/160fe4e7e5742c---nujimupov.pdfIn PDF document text
    • http://takeacode.com/user/d41d8cd98f00b204e9800998ecf8427e/file/49495377199.pdfIn PDF document text
    • https://www.advids.io/wp-content/plugins/formcraft/file-upload/server/content/files/1606fe975724be---pozipoxejebi.pdfIn PDF document text
    • http://monkey-do.net/userfiles/file/mikepibizomokizoge.pdfIn PDF document text
    • http://tgtech-auto.com/userfiles/file/sipag.pdfIn PDF document text
    • http://guoyangmoju.com/userfiles/files/88449049030.pdfIn PDF document text
    • http://energo-market.ru/sadm_files/tiwar.pdfIn PDF document text
    • http://ebsenglish.net/_UploadFile/Images/file/80024328857.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1xuhb7AK25c/uplcv?utm_term=free+media+player+for+windows+10+64+bitPDF 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_off0000fe54.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE54 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00011666.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11666 18584 bytes
SHA-256: 1d546f22e261b3c6d2012e79c36adbf37aebac4735ea85b082a40cc7601758b2
font_02_sfnt_off000146c5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x146C5 11396 bytes
SHA-256: 768a2dd958a940d7afc68f67aee4558176afa13978422c640c380ace56cc3f92

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