Malicious PDF — malware analysis report

Static analysis result for SHA-256 cb857f0643d9f0f5…

MALICIOUS

PDF

82.4 KB Created: 2021-09-23 20:51:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 5931afec680d521f8b838e721368bf0e SHA-1: 7f08e017385bd8f4ecc89a2749e1fbfdf0d95437 SHA-256: cb857f0643d9f0f5bbcd248335c88900f98fa0ea08b51b078f08d3fac756b9da
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is a PDF containing a link farm hosted on compromised WordPress sites, as indicated by multiple heuristics including 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM'. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or malware distribution. Although no scripts were directly extracted, the nature of the links and the detection suggest the PDF is designed to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

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 http://c2mag.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613a1f1c9072c---43184566516.pdf In PDF document text
    • http://utcsp2.rustyramone.com/uploads/files/femewad.pdfIn PDF document text
    • http://commandhousecreations.com/uploads/files/96045035907.pdfIn PDF document text
    • https://estduquebec.com/scripts/php/xenocode/lib/ckfinder/userfiles/files/89338156000.pdfIn PDF document text
    • http://guanzhuli.com/userfiles/file/xisuwegefigapumivodax.pdfIn PDF document text
    • http://systempro.kr/userData/board/file/17438265671.pdfIn PDF document text
    • http://nenorm.com/files/files/gasidip.pdfIn PDF document text
    • https://www.teppiche-waschen-hamburg.de/wp-content/plugins/formcraft/file-upload/server/content/files/1613fce38cf7c5---gulemadunefasofipirise.pdfIn PDF document text
    • https://paardenwelzijnscheck.nl/app/webroot/files/ckeditor_files/files/nunuludo.pdfIn PDF document text
    • https://cokhivietuc.com/img-vietuc/files/rakoxovogusodujew.pdfIn PDF document text
    • http://nokianhakkablue.ru/ckfinder/userfiles/files/lodilavezijeworubalanuso.pdfIn PDF document text
    • http://cbstav.cz/file/ponuwokogu.pdfIn PDF document text
    • http://www.jindatunnel.com/up_files/file/34614005210.pdfIn PDF document text
    • http://nwhouse.ru/uploads/file/51261496297.pdfIn PDF document text
    • http://www.oknookna.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1614bdd338fd97---46120798282.pdfIn PDF document text
    • http://ettorebelfioreliutaio.it/userfiles/files/xapolatitokiliwegapi.pdfIn PDF document text
    • http://bburago.info/admin/fckeditor/userfiles/file/jiwenakexaxetiz.pdfIn PDF document text
    • http://bestbelly.org/content/files/files/lariwof.pdfIn PDF document text
    • http://uat.ideadunes.com/projects/ideadunes-portfolio-site/wp-content/plugins/formcraft/file-upload/server/content/files/161403e7e7392c---10989956392.pdfIn PDF document text
    • http://resumesfromabove.com/userfiles/file/88920069363.pdfIn PDF document text
    • http://njchemland.com/upload/files/tuvejovazokamumopem.pdfIn PDF document text
    • https://photojet.net/userfiles/file/pezoxoxozomepabige.pdfIn PDF document text
    • http://ptaki.info/imgekoprojekty/files/vabalajametovosenadabo.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/6naE_Nh8_CY/uplcv?utm_term=bypass+frp+application+downloadPDF 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_off0000db2b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB2B 10732 bytes
SHA-256: 684fafa6231e3bfa91b251f28fc51d5d323a43b36a3c1f51abdcc4aa39f8900d
font_01_sfnt_off0000f411.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF411 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010c23.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C23 18400 bytes
SHA-256: 64ccdec1d11b254bbf66512ef37bf4ee0c75864d491a93b62becb276067f8af8

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