Malicious PDF — malware analysis report

Static analysis result for SHA-256 21a19368e1cc71e9…

MALICIOUS

PDF

80.9 KB Created: 2021-09-08 21:51:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 3b837ff7ea5e3bfbb211dfe9ba588b6c SHA-1: dd2438a49e3166c46ba7ea392ce29ae1569481b9 SHA-256: 21a19368e1cc71e9fbd75040137fc83e1144775cd99e318b79505c4f689b0fd1
164 Risk Score

Malware Insights

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

The sample is a PDF containing embedded JavaScript, which is a common technique for exploiting vulnerabilities or redirecting users. Heuristics indicate it functions as a link farm, directing users to multiple external URLs, some hosted on compromised or disposable domains. ClamAV detection as 'Pdf.Phishing.Trojan' further supports its malicious nature, suggesting it's used for phishing or delivering a secondary payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://www.benkorner.nl/admin/library/ckfinder/userfiles/files/ropavuxosave.pdf In PDF document text
    • https://nicemexico.net/wp-content/plugins/formcraft/file-upload/server/content/files/16133b39c8c39b---xalezibe.pdfIn PDF document text
    • http://boonfagrandhome.com/user_img/files/wewero.pdfIn PDF document text
    • http://przystaneknida.pl/data/aktualnosci_imgs/file/nituvowat.pdfIn PDF document text
    • https://vipbeachhouse.com/uploads/editor/file/fapamivaxibi.pdfIn PDF document text
    • http://vuatoyen.com/uploads/userfiles/file/86435129303.pdfIn PDF document text
    • http://www.lbtfilm.com/uploads/files/72785525145.pdfIn PDF document text
    • https://hockeymro.ca/docs/file/48425853282.pdfIn PDF document text
    • http://webinaris.biz/ckfinder/userfiles/publics/files/navewotapegiwusegur.pdfIn PDF document text
    • http://evergreendentistryva.com/app/webroot/js/ckfinder/userfiles/files/pesesitifatu.pdfIn PDF document text
    • http://nobody-films.com/bpms/includes/fckeditor_uploads/userfiles/file/tadeg.pdfIn PDF document text
    • https://maydongy.com/wp-content/plugins/super-forms/uploads/php/files/prkg9gojlp1hgv253cmc69mcah/80538369609.pdfIn PDF document text
    • https://jgranit.pl/userfiles/file/xudogesakofusabufoxumap.pdfIn PDF document text
    • https://mcq-exambd.com/app/webroot/ckfinder/userfiles/files/famizaxokarasadimegigi.pdfIn PDF document text
    • http://pnalog.ru/images/file/vajidifo.pdfIn PDF document text
    • http://a-range.ru/wp-content/plugins/formcraft/file-upload/server/content/files/161382d9af1852---79906440217.pdfIn PDF document text
    • http://billagelaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/mekojujorokuvul.pdfIn PDF document text
    • https://postelezmasivu-zlin.cz/ckfinder/userfiles/files/vuturalokedalixulus.pdfIn PDF document text
    • https://reparation-mobile.net/userfiles/file/71203003348.pdfIn PDF document text
    • http://xn----gtbercbfedtm3b.xn--p1ai/admin/ckfinder/userfiles/files/xukuxesubu.pdfIn PDF document text
    • http://aj-freight.com/ckfinder/userfiles/files/memozemov.pdfIn PDF document text
    • https://sweetestspaparty.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612fcf9a7104c---1010316555.pdfIn PDF document text
    • http://watch62.ru/files/files/43264406113.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/LPIa9PGmDLg/uplcv?utm_term=battle+cats+jp+mod+apkPDF 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_off0000d8c4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD8C4 10652 bytes
SHA-256: 73e4122a1f3982d1278b34b9bbaeebe531e35532d7206af4e3010a73c6eb1abd
font_01_sfnt_off0000f148.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF148 17248 bytes
SHA-256: 6860abb0a1f0a031bd7dbb7dd1a7553066aa3d27366baf6541ee670c12361c49
font_02_sfnt_off00011e12.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E12 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1