Malicious PDF — malware analysis report

Static analysis result for SHA-256 3bb1afd81bd70165…

MALICIOUS

PDF

83.0 KB Created: 2021-10-10 06:31:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: e6b6ee8604f5688c4797ae68acdefa30 SHA-1: c919a9e59618b559997d06f989fe5e1de6319a74 SHA-256: 3bb1afd81bd7016501a5bac95d6ea091c013628306f9931eae8c908fa340204e
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ML classifiers and ClamAV, with critical heuristics indicating it's a PDF phishing trojan. It contains embedded JavaScript and multiple external URIs, many of which point to potentially compromised WordPress upload directories or disposable hosting, suggesting a link farm designed to redirect users. The primary function appears to be directing users to malicious sites, likely for credential harvesting or further malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 7

  • 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.
  • 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://bestofbeer.ru/ckfinder/userfiles/files/bemogurepaf.pdf In PDF document text
    • http://warwick-ems.org/userfiles/file/wovukak.pdfIn PDF document text
    • http://salkim.com/userfiles/file/ganelagaxotuzute.pdfIn PDF document text
    • http://jlssj.com/qianzi/upfile/case_editor/file/gitufivikixamareral.pdfIn PDF document text
    • https://dmitrovka-zn.ru/admin/ckfinder/userfiles/files/66340950771.pdfIn PDF document text
    • http://stellarp.com/userfiles/file/11340639620.pdfIn PDF document text
    • https://www.chinacimctrailer.com/wp-content/plugins/super-forms/uploads/php/files/7b68b5dffa5c2269ecd75b0fc9b9dbd4/pexekojejekan.pdfIn PDF document text
    • https://by-express.com/upfiles/editor/files/38739240259.pdfIn PDF document text
    • https://www.prieur-equipement.com/ckfinder/userfiles/files/84660541705.pdfIn PDF document text
    • https://xn--1--8kcai1ck2bs.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/5995ead25567721668ad8e1bf7c8fec0/nukubajoretevebomubudipuf.pdfIn PDF document text
    • http://c2ctrading.org/cms_upload/files/19145562034.pdfIn PDF document text
    • http://historico.uts.edu.co/portal/app/ckfinder/userfiles/files/44048179141.pdfIn PDF document text
    • https://activepymes.com/pub/file/84122498356.pdfIn PDF document text
    • http://nassagroup.org/app/webroot/js/ckfinder/userfiles/files/zokutadala.pdfIn PDF document text
    • https://wtmasonry.com/ckfinder/userfiles/files/70001693366.pdfIn PDF document text
    • http://holidayinntorino.com/userfiles/files/defus.pdfIn PDF document text
    • http://xedaptap.net/userfiles/file/pojonesuketoputolozise.pdfIn PDF document text
    • http://hokkaido-love87.com/app/webroot/js/ckfinder/userfiles/files/nupofi.pdfIn PDF document text
    • https://klingende-zeder.de/wp-content/plugins/formcraft/file-upload/server/content/files/1614c2dd2256a6---42481745117.pdfIn PDF document text
    • http://denis-lefebvre-services.com/fichiers/file/jigebupoxeratevesafiduf.pdfIn PDF document text
    • http://pololanna.com/user_img/files/ditutobe.pdfIn PDF document text
    • http://es-manzokudou.com/yamituki-n/uploads/files/51891339958.pdfIn PDF document text
    • http://baominhlabors.com/upload/files/romasesafenikorilujep.pdfIn PDF document text
    • https://www.premiumtrade.ro/ckfinder/userfiles/files/jomupex.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/YTWXjIUwRh0/uplcv?utm_term=putting+two+pdf+files+togetherPDF 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_off0000df12.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF12 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f729.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF729 10804 bytes
SHA-256: 122070b3e1acd9775a981b2cadc60e633f2672268c4356761af4c999d0861319
font_02_sfnt_off00010fcf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10FCF 17848 bytes
SHA-256: 30d5f3060b51f54bb9dd90b0e5ece60a434e3ab56e8895b0fdffb8ef0d8f8413

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