Malicious PDF — malware analysis report

Static analysis result for SHA-256 8b259eb2b9494508…

MALICIOUS

PDF

74.0 KB Created: 2021-09-08 19:02:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: ea2b1ad799d6505c524ca13e10ee2ef7 SHA-1: b1af957de5b39fc81e69ead7a81644577695f7cf SHA-256: 8b259eb2b9494508df1d07b742f80cbdb1979cd3d8a4ab0c9702276498c6dd43
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF containing embedded JavaScript, which is a common technique for delivering malicious payloads or redirecting users to phishing sites. Several heuristics indicate the PDF is part of a link farm, with some links pointing to compromised WordPress sites, suggesting an attempt to obscure the true destination. The ML classifier and ClamAV detection strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://quanghuydulich.vn/img_duhoc/files/laxuxefinuzamonivejivi.pdf In PDF document text
    • http://njxinbell.com/upload/files/45691894634.pdfIn PDF document text
    • http://www.jacenter.org/js/ckfinder/userfiles/files/2866354531.pdfIn PDF document text
    • https://grupo-kayros.com/userfiles/file/tumafugejimikasebizirug.pdfIn PDF document text
    • https://vsevolozhsk.mebel18.com/uploads/files/vomagexanidasuxetor.pdfIn PDF document text
    • http://ville-dammarie.com/ckfinder/userfiles/files/fojuxamugipewelomukavi.pdfIn PDF document text
    • https://law.myvzl.com/wp-content/plugins/super-forms/uploads/php/files/d1vlq4jjivun11q3b2m25rs6m8/96617138719.pdfIn PDF document text
    • http://resortcrimea.com/ckfinder/userfiles/files/buvaxovudobu.pdfIn PDF document text
    • http://luyenthidhcanhsat.com/Images_upload/files/52969491339.pdfIn PDF document text
    • http://clingac.com/d/files/24041908976.pdfIn PDF document text
    • https://thewentworthco.com/wp-content/plugins/super-forms/uploads/php/files/d5sh7qthl7qh16p4ehk3mk71ad/13945507698.pdfIn PDF document text
    • http://askort.pl/Upload/file/zefofoparivalukogozebe.pdfIn PDF document text
    • https://studybrilliant.online/app/webroot/img/userfiles/file/22308208500.pdfIn PDF document text
    • http://productinfo.in/konadnew/userfiles/file/70896759359.pdfIn PDF document text
    • http://sancheonglittletheaters.com/upload/userfiles/2021/09/files/210908061521.pdfIn PDF document text
    • https://trexanh.net/upload/files/22153652130.pdfIn PDF document text
    • https://china-glass-mosaic.com/userfiles/files/20210831_184948.pdfIn PDF document text
    • http://actlogistic.vn/upload/editor/files/kerulenelaseroxuvubafeper.pdfIn PDF document text
    • https://njsolarpower.com/wp-content/plugins/super-forms/uploads/php/files/3bbcb2fb561d27c6d005cd931bc38da8/62930566151.pdfIn PDF document text
    • https://iwanbim.iwan.co/userfiles/files/ritiv.pdfIn PDF document text
    • https://www.cocochan.com.pk/wp-content/plugins/super-forms/uploads/php/files/9bac23615d9419b6073f72223bc84ffa/pemixe.pdfIn PDF document text
    • https://yennenga.org/business_school/uploads/file/64498246534.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3vuEKuznOb8/uplcv?utm_term=la+nouvelle+terre+eckhart+tolle+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_off0000bb3a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBB3A 17752 bytes
SHA-256: 4fc2c66fae8ba27a9807b5c3415c3da8d953bdf0530a0fa43ff01ffa639b98b8
font_01_sfnt_off0000e80a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE80A 10672 bytes
SHA-256: 8a7b766ebf126c2339a723f8185e3b9b8c7d101bb1bb799d2464dc7e1c744f65
font_02_sfnt_off0001007c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1007C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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