Malicious PDF — malware analysis report

Static analysis result for SHA-256 6a5db1431145312b…

MALICIOUS

PDF

80.6 KB Created: 2021-09-13 15:42:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 3456a15f5ed0f3462502e1cb4c228a2a SHA-1: c804ce34628a922881c7d85079b900937fdf075e SHA-256: 6a5db1431145312bd03826baccefd9307d204a004f67ea8de95e85a32fd04f55
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ClamAV and an ML classifier, with heuristics indicating embedded JavaScript and a link farm pointing to potentially compromised WordPress sites. The embedded JavaScript likely serves to execute malicious actions or redirect the user, while the link farm attempts to obscure the final destination. The presence of multiple external URIs and the PDF_SEO_DISPOSABLE_LINK_FARM heuristic suggest a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9917

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 http://assessmentinsight.com/ckfinder/userfiles/files/5368959863.pdf In PDF document text
    • http://ecofincas.net/ckfinder/userfiles/files/95106973435.pdfIn PDF document text
    • http://timebank.ru/sites/default/files/photos/pagefile/gigubot.pdfIn PDF document text
    • http://dentalcenterstudio.it/userfiles/files/69891059224.pdfIn PDF document text
    • http://drsrkbedcollege.com/ckeditor/ckfinder/userfiles/files/51153816980.pdfIn PDF document text
    • http://alphanaturehk.com/userfiles/file/25634554660.pdfIn PDF document text
    • https://shinyjewellers.com/wp-content/plugins/super-forms/uploads/php/files/5kggheuoinr3vcebjs21tq41od/jakusidox.pdfIn PDF document text
    • http://mudrkanuch.sk/editor_uploads/system/files/sanugemegoke.pdfIn PDF document text
    • https://ddriu.hu/wp-content/plugins/super-forms/uploads/php/files/a7f11368d21389e88c572dcfa65845eb/vupowiruvafonaba.pdfIn PDF document text
    • https://almondzwealth.com/administrator/imagetemp/file/51120620098.pdfIn PDF document text
    • https://adsbudget.net/userfiles/file/19122595439.pdfIn PDF document text
    • http://tunapvietnam.thietbiotoviet.com/Images_upload/files/39474595726.pdfIn PDF document text
    • http://duhochoangthanh.com/upload/files/bubelamonojaxonu.pdfIn PDF document text
    • https://www.medicalart.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/1613d352556ae4---83343263353.pdfIn PDF document text
    • http://www.physedu.in/newsite/userfiles/files/53368491056.pdfIn PDF document text
    • http://gearcon-eng.com/file_media/file_image/file/samomul.pdfIn PDF document text
    • https://www.pfgpartners.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1613e355c8bfbb---zikiwifaxixewo.pdfIn PDF document text
    • http://joyear.com/ckfinder/userfiles/files/bolibevifaduveg.pdfIn PDF document text
    • https://bokseinstituttet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/16134fcf9546d4---9596083449.pdfIn PDF document text
    • http://somkuthyoptika.hu/editor_up/83473559087.pdfIn PDF document text
    • https://kccegis.com/upfiles/content/file/20210910065035.pdfIn PDF document text
    • http://www.creativitaecomunicazione.it/js/lib/ckfinder/userfiles/files/kowubefeb.pdfIn PDF document text
    • https://globalcircle.club/userfiles/file/nukatiponeligodije.pdfIn PDF document text
    • http://d-a-s.cn/userfiles/file/borad.pdfIn PDF document text
    • http://spiregene.com/image/files/20210906_232240.pdfIn PDF document text
    • https://mi-stores.com/basketballtotaal/images/editor/file/13240267728.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/GLLx1DTH0VQ/uplcv?utm_term=tab+s6+lite+onenotePDF 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_off0000d73d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD73D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ef4f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF4F 17620 bytes
SHA-256: c9cf4ee97da2262753e731c5c90b0c884780cf479507afd4eda80de85d8d6e44
font_02_sfnt_off00011d1d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11D1D 10272 bytes
SHA-256: de9618d21bea5b026a6e8e4f452073e49eca8b4df438bf3cfc881e6d6defadf8