Malicious PDF — malware analysis report

Static analysis result for SHA-256 81b1f9fa3c9ff0c5…

MALICIOUS

PDF

73.4 KB Created: 2021-10-01 04:56:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 772146a802117a64fbb49a0bc6cae5c5 SHA-1: 888de730b380e21a8ce3bd28ed25b097a82e2c0e SHA-256: 81b1f9fa3c9ff0c52630ea8eceb34ef1e454a7e7bc06c560f62dd293211a31ce
134 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected by ClamAV as Pdf.Phishing.Trojan and flagged by an ML classifier, indicating malicious intent. It contains embedded JavaScript and numerous external URLs, suggesting it's designed to redirect users to malicious sites. The heuristic PDF_SEO_DISPOSABLE_LINK_FARM further supports the idea that this PDF is part of a link farm, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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
  • 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 https://inwebjor.ru/uplcv?utm_term=scheduled+power+on+off+android PDF link annotation
    • https://www.ventisilva.com.br/ckfinder/userfiles/files/58696533709.pdfIn PDF document text
    • https://heureka-cz.eu/files/sobuwapuxugeru.pdfIn PDF document text
    • https://ubk-sad.de/azubi/userfiles/files/16721766375.pdfIn PDF document text
    • http://mebel-moscow.com/content/xuploadimages/file/puzakujizip.pdfIn PDF document text
    • http://navigator-nsk.ru/userfiles/file/77834628380.pdfIn PDF document text
    • http://satit.nrru.ac.th/satit/_Adminis/ckfinder/userfiles/files/kadijarowigofenamadudu.pdfIn PDF document text
    • https://siliconautomation.com/userfiles/file/besarigil.pdfIn PDF document text
    • http://allefrgycg.news-read.com/upload/files/60281353920.pdfIn PDF document text
    • http://15449010.com/FileData/ckfinder/files/20210911_051269673D293BC6.pdfIn PDF document text
    • https://3redsquares.com/phpsites/vertical_living/uploads/file/98378461535.pdfIn PDF document text
    • http://www.wm-meyer.de/meyer/admin/editor/ckfinder/userfiles/files/radimi.pdfIn PDF document text
    • http://www.iuoelocal870.com/kaizen/ckfinder/userfiles/files/8396138873.pdfIn PDF document text
    • https://slicktechproducts.com/newerac2c/userfiles/file/waxerudowafofixunuxoxurez.pdfIn PDF document text
    • http://eperon-kochersberg.com/img_db/kozobejak.pdfIn PDF document text
    • https://onutglen.com/caningest/images/file/25242778600.pdfIn PDF document text
    • http://www.propper-droppers.nl/files/file/35435031655.pdfIn PDF document text
    • http://desushibar.com/userfiles/file/weledivo.pdfIn PDF document text
    • https://thehouseconcert.com/ckfinder/userfiles/files/89175315872.pdfIn PDF document text
    • http://woodbridgeabw.com/uploads/files/93564355781.pdfIn PDF document text
    • http://vititanon.com/user_img/files/48060614578.pdfIn PDF document text
    • http://oldmotorsclub.com/files/file/96887635613.pdfIn PDF document text
    • https://global-product.org/CKEdit/upload/files/bemadekikume.pdfIn PDF document text
    • http://nantong.chinatupai.com/web/js/ckfinder/userfiles/files/nagekufepizo.pdfIn PDF document text
    • https://www.diktu.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613aa0883cbae---21541273738.pdfIn PDF document text
    • https://thefertilizergranulators.com/d/files/16251194687.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_off0000b8c8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB8C8 10712 bytes
SHA-256: bd2a4283c0508d52522f2f498a1ae4f6d3b3627f01f8c20ff3beb2db13db204f
font_01_sfnt_off0000d157.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD157 17872 bytes
SHA-256: 4e76967c88319519808b261c056f71fb3f952bf3a8bd0502a9d559be6a2d1877
font_02_sfnt_off0000ff92.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF92 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1