Malicious PDF — malware analysis report

Static analysis result for SHA-256 c81db94620b5029c…

MALICIOUS

PDF

85.6 KB Created: 2021-09-03 04:42:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 928cd8529a8e49bd10800fae375b7419 SHA-1: af564de193a74f5e3d623736dda38c3054b4da3b SHA-256: c81db94620b5029c2660d7ff48a8492bf629f6875a53a5bbc0540d85029398cb
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which point to disposable hosting or compromised CMS upload directories, indicating a link farm designed to distribute malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware delivery. Although no scripts were explicitly extracted, the PDF structure and URL patterns are consistent with spearphishing attachments used to lure victims to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://audiohrestomatiya.ru/content/file/wujukusotuludugura.pdf In PDF document text
    • http://pm-ural.com/uploads/files/volilerovobu.pdfIn PDF document text
    • https://dafelia.com/files/gerawagem.pdfIn PDF document text
    • http://burragebrothers.org/demo/jolie/beta/userfiles/files/36233401765.pdfIn PDF document text
    • https://betonwerkendejonge.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1608099b43f448---44921157267.pdfIn PDF document text
    • https://hssipm.com/wp-content/plugins/super-forms/uploads/php/files/85e1748201424d47a17f952eebfb6aae/29771364063.pdfIn PDF document text
    • https://tectrongim.com/uploads/files/95837236339.pdfIn PDF document text
    • http://grodgolf.com/clients/f/fd/fd83fa7079552abb47853a85229f74c1/File/56750001354.pdfIn PDF document text
    • http://localhomesales.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160aafc5444e85---bopazagemexadonufolu.pdfIn PDF document text
    • https://srsatta.com/ckfinder/userfiles/files/bonuvelopurasux.pdfIn PDF document text
    • https://www.sharpeningfactory.com/wp-content/plugins/formcraft/file-upload/server/content/files/160948e5c5caae---fawuv.pdfIn PDF document text
    • http://centralcogtc.com/uploads/file/43440472885.pdfIn PDF document text
    • http://buddhavehicle.com/userfiles/file/dagezefizemibozegalaxiwil.pdfIn PDF document text
    • http://amon-syotengai.com/userfiles/file/fovojilixu.pdfIn PDF document text
    • http://exclusivelimoservice.com/ckfinder/userfiles/files/89069801872.pdfIn PDF document text
    • https://fajndoktor.cz/images/file/files/jogukitug.pdfIn PDF document text
    • https://artofsurfing.com/preview/ckfinder/userfiles/files/vujokijogunimitunojifuwe.pdfIn PDF document text
    • http://patp1ryb.ru/media/file/dadazinud.pdfIn PDF document text
    • http://bijverhoeven.nl/uploads/files/sapukaxigogodirire.pdfIn PDF document text
    • http://immobilieninvestors.de/userfiles/file/xibogelafadanevikuve.pdfIn PDF document text
    • http://bukharajohnscreek.com/sites/default/files/file/16285160534.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/zMnd8XtcwSM/uplcv?utm_term=skulduggery+pleasant+book+12+pdfPDF 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_off0000e917.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE917 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010129.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10129 17512 bytes
SHA-256: 5e3f9bd1919ddd6bb2f393a6e5aca42958f8bd6696f9d6b7318d7d91a4744649
font_02_sfnt_off00012e9d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12E9D 11272 bytes
SHA-256: 12364402ac901588ce55aa66b3dfb98da05af42580f6c62f274e428c7127791d