Malicious PDF — malware analysis report

Static analysis result for SHA-256 4f4a61d71373cf36…

MALICIOUS

PDF

83.8 KB Created: 2021-07-08 08:42:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 8f53173e7150a8abe373a0da54111903 SHA-1: ecfea121caeac05becb4d28cd8bdab8d10092acf SHA-256: 4f4a61d71373cf36d2b00d4698f0805ecda08dc7100a59fb9f8f9056db857d49
156 Risk Score

Malware Insights

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

The PDF document was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing or trojan delivery mechanism. Heuristics indicate it functions as a link farm, directing users to multiple compromised WordPress upload storage locations and disposable hosting sites. The embedded URLs, such as 'https://inwebjor.ru/uplcv?utm_term=claiming+internet+on+tax', are likely used to distribute further malicious content or phish for credentials.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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 https://inwebjor.ru/uplcv?utm_term=claiming+internet+on+tax PDF link annotation
    • http://cngwalk.com/fckeditor/userfiles/image/pezasewedore.pdfIn PDF document text
    • https://psychotherapie-dr-albrecht.de/wp-content/plugins/formcraft/file-upload/server/content/files/16099eadade4fb---92462378907.pdfIn PDF document text
    • https://riverasphotovideo.com/wp-content/plugins/formcraft/file-upload/server/content/files/16077881856f57---23975936134.pdfIn PDF document text
    • https://planet-for-events.de/userfiles/file/44365323365.pdfIn PDF document text
    • https://www.properties-thassos.com/wp-content/plugins/super-forms/uploads/php/files/39o5kiqr5e19f105qnpbh7fgfs/fitir.pdfIn PDF document text
    • https://bishopsalamatkhokhar.org/userfiles/file/68821492545.pdfIn PDF document text
    • https://imapcb.org/wp-content/plugins/super-forms/uploads/php/files/d6b104a6232051b6f3937cc9d83dba5d/9527396295.pdfIn PDF document text
    • http://prime-standard.com/piceditor/file/46210262161.pdfIn PDF document text
    • http://riversreunion.org/clients/8699/File/59102025651.pdfIn PDF document text
    • http://files.ibiza-ferien.de/file/kikobibedabivumulug.pdfIn PDF document text
    • https://www.ezhealthcheck.com/wp-content/plugins/super-forms/uploads/php/files/pepopccnrrnc3epe7tf240p9rs/jeragu.pdfIn PDF document text
    • http://test.uebersetzungen-nesselberger.de/wp-content/plugins/formcraft/file-upload/server/content/files/1606f1a9d206c4---jujavanevuvubazosisonel.pdfIn PDF document text
    • https://aulacvn.com/upload/fck/file/munepusegowevazud.pdfIn PDF document text
    • http://limpiasol.com/wp-content/plugins/formcraft/file-upload/server/content/files/160874e6eca6f5---30823023325.pdfIn PDF document text
    • http://yuseigachi.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160d0a0bb91b16---xujorogeki.pdfIn PDF document text
    • https://echipamente-scule.ro/userfiles/file/93850122198.pdfIn PDF document text
    • https://orkhaconstruction.com/wp-content/plugins/super-forms/uploads/php/files/g9af7bcqkvh0luseap7tgk64m7/kegajademuwugiwepox.pdfIn PDF document text
    • https://www.kiteschule-kiel.de/wp-content/plugins/formcraft/file-upload/server/content/files/16092cfea6396c---wigokofi.pdfIn PDF document text
    • https://toskov-yordanov.com/userfiles/file/57794364810.pdfIn PDF document text
    • http://selfmadefilms.nl/userfiles/files/mavuravimaradofi.pdfIn PDF document text
    • http://www.cenlaenvironmental.com/siteuploads/editorimg/file/25894022386.pdfIn PDF document text
    • http://shuswapladystriders.ca/userfiles/file/8724200985.pdfIn PDF document text
    • http://www.linkkorea.co.kr/wp-content/plugins/formcraft/file-upload/server/content/files/160b93622526ed---gisofigururo.pdfIn PDF document text
    • https://stollerco.com/testingsites/advantage_aviation/assets/media/file/29809051194.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_off0000e882.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE882 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010099.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10099 10416 bytes
SHA-256: d921455746372b9dd2d053f27becd11e054103e44a5b905515f4b719bbd040d5
font_02_sfnt_off00011828.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11828 16084 bytes
SHA-256: 02b4ffd2327dccb7c861b5936be7615156d7a2274570b7f8bc62bd99f00d0de0

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