Malicious PDF — malware analysis report

Static analysis result for SHA-256 5c66bb760b9c0b0a…

MALICIOUS

PDF

86.9 KB Created: 2021-09-13 16:26:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: b03207b8ca8ccb1a33c79be26e4d072c SHA-1: 6f5a7100b200a0d032b4dec024b4e9f73f53aa7c SHA-256: 5c66bb760b9c0b0a160fd5f235920cf8f3dccba4e67d8060aeae5e1a335b4c27
156 Risk Score

Malware Insights

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

The file is a PDF identified as malicious by ML classifiers and ClamAV. It functions as a link farm, containing numerous URLs pointing to other PDF files hosted on compromised WordPress sites and disposable domains. This suggests an attempt to distribute malicious content or conduct phishing by chaining multiple compromised resources.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

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 https://www.brunosistemi.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139aedeb1cc7---zovef.pdf In PDF document text
    • https://korovin.org/site/img_ufiles/venipalija.pdfIn PDF document text
    • http://coreaad.com/DreamDataUpload/file/10555493095.pdfIn PDF document text
    • http://www.jobsincrete.gr/images/_user_na/file/51457583025.pdfIn PDF document text
    • https://youkuvpn.com/upload/files/pilabipufovuritidiluravuv.pdfIn PDF document text
    • http://paddockj.com/user_data/editor/ckfinder/core/connector/php/upload/files/39495941217.pdfIn PDF document text
    • http://banhangcongnghe.com/upload/FCK/file/98873586688.pdfIn PDF document text
    • http://lagrupacio.cat/file/7388481558.pdfIn PDF document text
    • https://www.kindspring.org/inc/ckfinder/userfiles/files/36398806675.pdfIn PDF document text
    • http://sergeybazarov.ru/file/73914930001.pdfIn PDF document text
    • http://sinoscaform.com/upload/ckimg/files/202109060458529254.pdfIn PDF document text
    • http://www.ebsjosepirosamaria.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613c0a74e80bd---nipigevunetebawekusa.pdfIn PDF document text
    • http://alibabashipping.com/userfiles/file/30012228108.pdfIn PDF document text
    • https://needlugs.com/userfiles/files/ritirogikolobijagetifuge.pdfIn PDF document text
    • https://truongthanhco.vn/webroot/img/files/32127483182.pdfIn PDF document text
    • http://bytip.net/filespath/files/20210906013520.pdfIn PDF document text
    • http://rockhouseschool.com/rockhouse/uploads/files/penejuwaxinowuvawuze.pdfIn PDF document text
    • http://brainbond.ro/userfiles/file/98472857097.pdfIn PDF document text
    • https://likeevent.it/writable/public/userfiles/file/dadoxisuzev.pdfIn PDF document text
    • http://vibrosystem.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1613ae56875ce3---91410806878.pdfIn PDF document text
    • http://cnzhongkui.com/fckeditor/editor/filemanager/connectors/php/uploads/file/121941477605.pdfIn PDF document text
    • http://miydz.com/mingyi/images/userfiles/file/wawobitijogumelez.pdfIn PDF document text
    • http://jiin-torng.com/uploadfiles/20210904181009.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/YTWXjIUwRh0/uplcv?utm_term=dagger+inject+constructorPDF 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_off0000ed3c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED3C 10588 bytes
SHA-256: 6690580fa3010d3a4822f84cd8335387a8365b5f2a306541a074157c9bdef370
font_01_sfnt_off00010587.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10587 18612 bytes
SHA-256: 231d5733b70619add0e022231b408788c58714477ebbce5159b7ae1560103e5e
font_02_sfnt_off0001368a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1368A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1