Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef133dd87555cba6…

MALICIOUS

PDF

71.8 KB Created: 2021-09-30 18:23:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: eb6575739b9b8ab4e9a213d2b577c423 SHA-1: b955a711ef68ac8fbfb95a5caee6c3f1fdaf953c SHA-256: ef133dd87555cba636975a5c86276347c004c0515a15ef928d2cdfc3ff24e930
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, indicating it likely contains malicious content. It functions as a link farm, with numerous embedded URLs pointing to various domains, many of which are associated with compromised CMS uploads or disposable hosting. The document body is heavily obfuscated and unreadable, suggesting it is not intended for direct user interaction but rather to host these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

Heuristics 6

  • 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.
  • 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://xfswchem.com/upload/files/ziruxale.pdf In PDF document text
    • http://nomayaku.com/userfiles/file/2394613842.pdfIn PDF document text
    • https://praktijkbinnenstad.nl/file/bilazamaxev.pdfIn PDF document text
    • https://118highschool.am/wp-content/plugins/super-forms/uploads/php/files/1af4dd5afa7cd7e65c396f34e6f8497e/95357888965.pdfIn PDF document text
    • https://ofly.om-digitalsolutions.cn/upload/files/18829737725.pdfIn PDF document text
    • https://gestionarival.com/userfiles/file/28410389507.pdfIn PDF document text
    • https://3rproject.eu/ckfinder/userfiles/files/80961014472.pdfIn PDF document text
    • http://gopherandsquirrelcontrol.com/admin/images/file/purede.pdfIn PDF document text
    • https://strechybenesov.cz/content/25258162902.pdfIn PDF document text
    • https://rockeit.com/userfiles/file/defifeto.pdfIn PDF document text
    • http://ministerium.pt/files/nobonolujubakovotozux.pdfIn PDF document text
    • https://qatarsecurityservices.com/public_html/userfiles/file/lusutatudogu.pdfIn PDF document text
    • https://vleek.com/uploads/files/todevejuk.pdfIn PDF document text
    • http://www.predoisiasociatii.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1614d748c81e88---rapigesaxurofeporog.pdfIn PDF document text
    • http://ziguratex.com/helpdesk/app/webroot/img/userfiles/files/36176018091.pdfIn PDF document text
    • http://gowowdeli.com/uploads/files/semeselezikipelomipotoke.pdfIn PDF document text
    • https://militarynetwork.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1613e000b68af5---75945354536.pdfIn PDF document text
    • https://clinicaalcantara.es/sites/default/files/userfiles/file/dorudap.pdfIn PDF document text
    • http://ciarajewellery.com/editor_upload/file/nosog.pdfIn PDF document text
    • https://998.geektic.com/geektic/files/47823994050.pdfIn PDF document text
    • http://alrabbancapital.com/file/files/nikujojavowebowokaxi.pdfIn PDF document text
    • http://melodylavernebettencourt.com/media/file/5803025472.pdfIn PDF document text
    • https://aldea.work/wp-content/plugins/super-forms/uploads/php/files/1a9462ccdde95f478811097814000fdb/99935887552.pdfIn PDF document text
    • http://szpital-sulecin.pl/images/fckfiles/file/45555146412.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/S30rS-6n6vg/uplcv?utm_term=gta+paid+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_off0000b4bc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB4BC 9844 bytes
SHA-256: 8013a760f8fdf7c01ae0af786bd5a89e966ce0234ee6bdb71bff6fa4513690d5
font_01_sfnt_off0000ca81.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCA81 18548 bytes
SHA-256: d48a3a020c304665e21ae1d3eefc006e023bf952f0dbfe8ca64c990ea0840bc5
font_02_sfnt_off0000fa21.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA21 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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