Malicious PDF — malware analysis report

Static analysis result for SHA-256 bcbf73481445b05c…

MALICIOUS

PDF

114.0 KB Created: 2021-09-06 10:11:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: b61ac97445e34c5bf598732cd1261695 SHA-1: 8a87f0383a4c19d985d934510eebba11657a450d SHA-256: bcbf73481445b05c3b8304996b74e9a41db241059f59b042b84b25667c265e45
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised websites or are part of link farms designed to obscure the final destination. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware delivery through these links. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing content to analyze.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

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://birzebbugastpetersfc.com/files/file/sifidog.pdf In PDF document text
    • http://www.caribbeandentist.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609550089dc9c---papimizenejusug.pdfIn PDF document text
    • http://www.tiande-global.com/ckfinder/userfiles/files/varesuseguda.pdfIn PDF document text
    • http://zbraneklapka.cz/ckfinder/userfiles/files/wotemogoxuridexaseb.pdfIn PDF document text
    • https://verlauf-ekb.ru/admin/ckfinder/userfiles/files/niregeli.pdfIn PDF document text
    • https://nothingbutsafetyglasses.com/userfiles/file/wavonikugevamoxidaxaxov.pdfIn PDF document text
    • http://innova-perila.ru/upload/files/87389622854.pdfIn PDF document text
    • https://sanaspinler.com/calisma2/files/uploads/febikabaguwumabifazesoje.pdfIn PDF document text
    • http://bukharaalpharetta.com/sites/default/files/file/rugajotalurudotirolibibov.pdfIn PDF document text
    • http://yaqeen-eg.com/userfiles/file/limiranedasikujew.pdfIn PDF document text
    • https://travolution.travel/wp-content/plugins/super-forms/uploads/php/files/39321ba367384e17b3f39afbb6d7e6a4/68953508665.pdfIn PDF document text
    • http://folientastaturen.pl/_data/file/robig.pdfIn PDF document text
    • http://turskazka.ru/ckfinder/userfiles/files/rukamigedinalelojixevu.pdfIn PDF document text
    • https://stillwaiting.org/userfiles/file/36508179805.pdfIn PDF document text
    • http://tumwebthailand.com/ckfinder/userfiles/files/94967056125.pdfIn PDF document text
    • http://brightwayconsultancyservices.com/userfiles/file/bufojivofoxevutekalij.pdfIn PDF document text
    • https://morethancleaningservices.com/wp-content/plugins/super-forms/uploads/php/files/25bf004b335e9273143d77d32e72a99d/gofuf.pdfIn PDF document text
    • http://arabic.cz/ckfinder/userfiles/files/wujinu.pdfIn PDF document text
    • https://www.saltriot.com/wp-content/plugins/super-forms/uploads/php/files/8295597f3bcfc054eadfaf2adfb3e50a/2463803783.pdfIn PDF document text
    • http://rolmech-strzelno.pl/Upload/file/favatomewepuwom.pdfIn PDF document text
    • https://floridainvestment.cz/files/file/21259970593.pdfIn PDF document text
    • https://planet-pvc.com/upload/files/pibivarotebafada.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/ngfLrbzwjls/uplcv?utm_term=leadership+challenge+book+pdfPDF 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_off00015939.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15939 10988 bytes
SHA-256: f968f42abf01108baaefaf36d63d195aa82773628e3d32d7a788989323c56bec
font_01_sfnt_off0001722b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1722B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00018a3d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x18A3D 18672 bytes
SHA-256: ec47a0f2c25154637fbeb666e89bca9c15c618458f4dc7b52a4eeb715ad4b43f

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