Malicious PDF — malware analysis report

Static analysis result for SHA-256 4fc65d8d99d777a0…

MALICIOUS

PDF

82.0 KB Created: 2021-09-21 14:02:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 6079859ba998399a5c92fd6add21857b SHA-1: 1288d3b404dea6a8f26a6f437fce047384a1c40b SHA-256: 4fc65d8d99d777a0d6090fc15cf156eee741a5bd8b944fd0e0902089f9e7e6a4
156 Risk Score

Malware Insights

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

The PDF file was flagged by ClamAV as a phishing trojan and ML classifiers indicated a high probability of maliciousness. The document contains a link farm with numerous URLs, many of which point to compromised websites or disposable hosting, suggesting an attempt to redirect users to malicious content. The presence of multiple PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics further supports this attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9911

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://hosrem.org.vn/ckfinder/userfiles/files/15480166317.pdf In PDF document text
    • https://psfund.org/public/uploads/files/cms_files/27562387906.pdfIn PDF document text
    • https://www.la-melodie-des-saveurs.fr/ckfinder/userfiles/files/76000227266.pdfIn PDF document text
    • http://mouaumfb.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614112334af52---kotatufusegiponurem.pdfIn PDF document text
    • http://letnipohar.cz/upload/file/56026033848.pdfIn PDF document text
    • http://jandebruijn.com/uploadimages/files/19969491643.pdfIn PDF document text
    • http://www.agot.pl/upload/file/61222878296.pdfIn PDF document text
    • http://probeg2000.ru/files/userfiles/files/takizawigekatajod.pdfIn PDF document text
    • http://susutour.com/userfile/file/79515338231.pdfIn PDF document text
    • http://umbabox.com/userfiles/file/dekitazadetutifiwawus.pdfIn PDF document text
    • http://ptk-astana.kz/wp-content/plugins/super-forms/uploads/php/files/01321444a4d7a15f92af72e39db9f5f5/gakofiserupolarigaxereka.pdfIn PDF document text
    • http://lifecontinues.ru/images/files/genazawer.pdfIn PDF document text
    • https://vinaarc.com/app/webroot/files/ckfinder/userfiles/files/34815351842.pdfIn PDF document text
    • http://braciszewska-klimek.pl/fck_files/file/59705966028.pdfIn PDF document text
    • http://divorcefinance.nl/uploads/file/23120950021.pdfIn PDF document text
    • https://noelex22.org/userfiles/file/kozisapedox.pdfIn PDF document text
    • http://trendstyleimage.com/uploads/ckfinder/userfiles/files/melatebumegoz.pdfIn PDF document text
    • http://nfrostov.ru/upload/files/weluderujipe.pdfIn PDF document text
    • https://sketchup360.vn/wp-content/plugins/super-forms/uploads/php/files/t0v3fq46bma6sfvguo2lh2gehm/pesufijolorekaved.pdfIn PDF document text
    • http://absolutelyneon.com/userfiles/file/totadojoginiti.pdfIn PDF document text
    • https://suativisamsungtaihanoi.net/upload/files/sazemepodazolajazu.pdfIn PDF document text
    • http://tko.wavedev.net/img/files/files/jefuj.pdfIn PDF document text
    • http://hastensandbreakfast.nl/userfiles/file/87189421152.pdfIn PDF document text
    • https://maydongy.com/wp-content/plugins/super-forms/uploads/php/files/h7fooko955pjkmd3femcqg2p7f/ronoxef.pdfIn PDF document text
    • http://marketingnews.fr/images/file/87093096783.pdfIn PDF document text
    • http://vibrobreaker.com/files/files/wubaxagewu.pdfIn PDF document text
    • http://starma.pl/files/file/7196699845.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/fzgW7-mxBc0/uplcv?utm_term=how+to+set+up+nhs+net+email+on+androidPDF 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_off0000d970.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD970 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f182.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF182 18256 bytes
SHA-256: c56b346774a67b858c3707c0a0df1907daaa445f9016d713cf669bfd5964b745
font_02_sfnt_off00012135.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12135 10836 bytes
SHA-256: c8272da8ed122e4bf0d58a6d2c4d20ac344bdb63384bed8594c81af51b09feb3

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