Malicious PDF — malware analysis report

Static analysis result for SHA-256 b25cfb1831dba705…

MALICIOUS

PDF

80.1 KB Created: 2021-09-20 11:21:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: e455febf9d41a8ab50aee5bf2c979862 SHA-1: d32f9ea88dc2d818422c4b6f11f0d90eb1eecd46 SHA-256: b25cfb1831dba705340a688ef6cdce9addeeb0fb453f199405911db55db63903
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a large number of external URIs and links to compromised CMS uploads, indicating it functions as a link farm. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or SEO spam. No scripts were extracted, but the structure and URL patterns are indicative of malicious activity.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9949

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=android+floating+home+button PDF link annotation
    • https://getadoc.in/ckfinder/userfiles/files/25483577282.pdfIn PDF document text
    • https://woft-dining.com/webroot/editor-uploads/files/xivonulavu.pdfIn PDF document text
    • https://www.auto-ecole-acm.com/ckfinder/userfiles/files/ditenara.pdfIn PDF document text
    • https://protradingindia.net/userfiles/file/82034641723.pdfIn PDF document text
    • http://xn--h1aeekk.xn--p1ai/files/file/75116670731.pdfIn PDF document text
    • https://www.reliancecareuk.com/wp-content/plugins/super-forms/uploads/php/files/47f9e47c780ed7fff4f05d857cae6961/nowul.pdfIn PDF document text
    • http://vlajkylevne.cz/UserFiles/File/74857489678.pdfIn PDF document text
    • http://hieuchuan.com/upload/files/77396703569.pdfIn PDF document text
    • http://mitsubishilongbien.vn/images/ckeditor/files/kupuvusabu.pdfIn PDF document text
    • https://bikidi.com/UpFiles/WebEditorFiles/file/49375498540.pdfIn PDF document text
    • http://osoboebludo.com/ckfinder/userfiles/files/fakuwulabu.pdfIn PDF document text
    • http://xn--80aab8aioy.xn--p1ai/userfiles/file/35215934005.pdfIn PDF document text
    • http://sochi-riba.ru/ckfinder/userfiles/files/gonefawadenuw.pdfIn PDF document text
    • http://furkansigorta.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/16147fd977c0e8---ligivaginabuda.pdfIn PDF document text
    • http://mvsexpo.ru/admin/ckfinder/userfiles/files/wejudajiborufijevenejep.pdfIn PDF document text
    • http://biosurfest.com/userfiles/files/31324947446.pdfIn PDF document text
    • http://longchimvac.net/app/webroot/uploads/files/zebajuzusakatadekidonuzud.pdfIn PDF document text
    • https://hobbypet.cz/files/file/51230895195.pdfIn PDF document text
    • https://refundsrefunds.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613746cee1d8d---zexibulim.pdfIn PDF document text
    • https://5ky13lu3-1251.com/contents/files/zoxiloxepiwoso.pdfIn PDF document text
    • https://callhfelectric.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613dbf50bf5ec---2349266620.pdfIn PDF document text
    • https://nuevocoach.co.uk/wp-content/plugins/super-forms/uploads/php/files/58f8cfa2fc4e42f8b0ae3f7091baea24/91500276148.pdfIn PDF document text
    • http://geosond.pl/userfiles/file/pukomolonupomukidobofowaj.pdfIn PDF document text
    • http://dieterheich.de/images/uploads/file/nuxujelezitozadibukisowu.pdfIn PDF document text
    • http://xn--90aoa5aj.xn--p1ai/ckfinder/userfiles/files/33896646030.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_off0000d43b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD43B 17664 bytes
SHA-256: 0800827cb6d3a6771deaac9fd96e23ebec169977bce53f5fa78ae161a86225a8
font_01_sfnt_off00010266.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10266 10856 bytes
SHA-256: f2390f139208db8503b5cce7f29725ad76edb4e83de88459b70c9ab4d6247ece
font_02_sfnt_off00011b01.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11B01 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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