Malicious PDF — malware analysis report

Static analysis result for SHA-256 81c7d76c1b20bcbb…

MALICIOUS

PDF

82.5 KB Created: 2021-09-17 23:19:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: c922d29c3d7748708cc1d250132a01d9 SHA-1: a9515877934be1f8bb9833755cd294b9b55464fe SHA-256: 81c7d76c1b20bcbbd035d29b0c87d69bd6c86782219ddc1cabfb70c3e9a707cc
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript and numerous external URIs, many of which point to compromised WordPress upload directories or disposable hosting, indicating a link farm designed to distribute malicious content. ClamAV and ML classifiers confirm its malicious nature, flagging it as a phishing trojan.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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://sklepjola.pl/userfiles/file/vojepisajadik.pdf In PDF document text
    • http://circuitvietnamcambodge.com/hinhanh/file/89976889608.pdfIn PDF document text
    • http://maydemtienvn.com/upload/files/muremuzivopu.pdfIn PDF document text
    • https://miltonmattox.com/userfiles/file/lemowa.pdfIn PDF document text
    • http://fruhmann-elektrotechnik.at/13574692944.pdfIn PDF document text
    • http://cyuanmei.com/userfiles/file/wonizetulenifobitunuwira.pdfIn PDF document text
    • http://btfa.tw/upload/files/tusaxu.pdfIn PDF document text
    • http://balbu.hu/uploads/news/file/nometezigojoluf.pdfIn PDF document text
    • http://hydrem.ru/images/file/jimugowugexosa.pdfIn PDF document text
    • https://brylka-kfz.de/wp-content/plugins/formcraft/file-upload/server/content/files/161343ac23f8ac---wapovonazevam.pdfIn PDF document text
    • https://vongtaytramhuong.vn/upload/files/47906970758.pdfIn PDF document text
    • http://limpiasol.com/wp-content/plugins/formcraft/file-upload/server/content/files/161359f17170e9---41475594564.pdfIn PDF document text
    • https://brukspec.pl/upload/file/tasiroguvowapajuf.pdfIn PDF document text
    • http://www.dagmarsvendova.cz/admin/js/ckfinder/userfiles/files/jobenotodugaramevaluje.pdfIn PDF document text
    • https://wtmasonry.com/ckfinder/userfiles/files/17188895769.pdfIn PDF document text
    • http://eko-uklid.com/files/file/94699512937.pdfIn PDF document text
    • https://pellevah.com/upload/files/didixilof.pdfIn PDF document text
    • https://cafesca.org/ckfinder/userfiles/files/77333942562.pdfIn PDF document text
    • http://daimarconstrucciones.com/images/admin/file/10386320399.pdfIn PDF document text
    • http://stressmanagement-karriere.de/userfiles/file/wekigidotifike.pdfIn PDF document text
    • https://ww150007.linebot.net/upfile/files/20210902033031.pdfIn PDF document text
    • http://av72-reklama.ru/userfiles/file/163099869392539a5492fe6ef1e737.pdfIn PDF document text
    • https://vpmemorial.net/images/file/petet.pdfIn PDF document text
    • http://cuoredicane.it/userfiles/files/31078531644.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=playstation+games+for+android+apkPDF link annotation
    • https://bxthirteen.wpengine.com/wp-content/plugins/super-forms/uploads/php/files/2f234e5e88b01b2759f59371e8a3e660/36582691120.pdfIn PDF document text
    • 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_off0000de61.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE61 17068 bytes
SHA-256: 9afbb7a8a5caac6c36f39517deecd16e6da9daec119184d30ccaf51f30bdf82d
font_01_sfnt_off00010a8c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A8C 11048 bytes
SHA-256: 1bcef84f77c11188225c05c7f19d4ee5c714520beef49f69c2ccbbde918d9e1a
font_02_sfnt_off0001241d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1241D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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