Malicious PDF — malware analysis report

Static analysis result for SHA-256 61c8290ecef0df2b…

MALICIOUS

PDF

83.5 KB Created: 2021-08-23 10:18:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: ef2738ec69119f8c57329bf82655793a SHA-1: 30ce5b4020b44cee5ec595bb0b76a9ca4fe249fb SHA-256: 61c8290ecef0df2ba28f1cce8d8357ac675923f4880782c76c22ab14f5fde439
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 compromised WordPress upload storage. The embedded JavaScript likely facilitates the redirection to external URLs, which are part of a link farm designed to obscure the final destination, potentially leading to phishing or malware downloads. The presence of multiple PDF files within compromised CMS upload directories suggests a coordinated effort to host malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

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 https://www.pferde-fuer-unsere-kinder.de/wp-content/plugins/formcraft/file-upload/server/content/files/160a9d1caa14a9---3603655838.pdf In PDF document text
    • http://nano-vip.com/ckfinder/userfiles/files/55335202402.pdfIn PDF document text
    • http://caratow.eu/userfiles/file/vosive.pdfIn PDF document text
    • http://brenno-tojestto.pl/userfiles/file/votezameruwoloxubase.pdfIn PDF document text
    • http://exim5.hu/_user/file/tifuwatavo.pdfIn PDF document text
    • https://www.infratechgroep.nl/wp-content/plugins/super-forms/uploads/php/files/1eb878b6e8c96afe894f95af1e2b180d/61495504991.pdfIn PDF document text
    • https://lawweb.info/mycms/admin/userfiles/file/mufilunudajogejixetoji.pdfIn PDF document text
    • http://langfordfinancialservices.com/userfiles/files/5203618168.pdfIn PDF document text
    • http://urbanconstructions.org/images/uploadedimages/file/mirazuguvurufilavivej.pdfIn PDF document text
    • http://localhomesales.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160ee341765ce1---nuxefabasisumijuposuxane.pdfIn PDF document text
    • http://www.thaiboat.net/image/upload/File/25023361461.pdfIn PDF document text
    • http://nt-module.ru/ckfinder/userfiles/files/zoloziwejejodosovusogi.pdfIn PDF document text
    • http://averon.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160a79cc6438d9---68950047728.pdfIn PDF document text
    • http://steclotildehorton.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160ac881b23003---63609642954.pdfIn PDF document text
    • http://due.pt/js/ckfinder/userfiles/files/dutubifamopiperebefudulo.pdfIn PDF document text
    • http://www.phonefixcomo.com/wp-content/plugins/formcraft/file-upload/server/content/files/16073773be3188---beludokujamagakimume.pdfIn PDF document text
    • https://pfgmm.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160a6d08255a4e---suripapipusesanij.pdfIn PDF document text
    • http://greenbrier101.com/userimages/wogozezubabanugotu.pdfIn PDF document text
    • http://cameronhaddock.com/wp-content/plugins/formcraft/file-upload/server/content/files/16083df746c6e3---52514839430.pdfIn PDF document text
    • http://www.hptindia.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608587886f164---roxetuduvodubuvaf.pdfIn PDF document text
    • https://tootooair.com/FileData/ckfinder/files/20210625_40122D7B34E0B162.pdfIn PDF document text
    • http://www.rebranded.tv/wp-content/plugins/formcraft/file-upload/server/content/files/160abf07caed4b---simupepejopaw.pdfIn PDF document text
    • https://mebelpozakazu.ru/wp-content/plugins/super-forms/uploads/php/files/8f6c42724c53aec05ca95ff982390b7c/96842850399.pdfIn PDF document text
    • https://sumangold.net.vn/wp-content/plugins/super-forms/uploads/php/files/0sggucia8oj3rabuq2d275ekpa/34784546439.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1KS0DP0cxss/uplcv?utm_term=how+to+find+the+axis+of+symmetry+on+a+graphPDF 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_off0000e11f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE11F 16620 bytes
SHA-256: 9e4376cf4c1748193286d55a923339683ab60abc6a9012f42cfab4017fab2655
font_01_sfnt_off00010bde.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10BDE 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000123f5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x123F5 11192 bytes
SHA-256: 3cd93322ae32d3ce44b62c07c8176b663ff69a0c90563124a0ddfc7ffaa0c4a3

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