Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4fd49d7ebab9125…

MALICIOUS

PDF

71.0 KB Created: 2021-09-19 23:41:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: a5c9ef856becf968db091ea76f631948 SHA-1: 006e50f02bb26b822278801c72dc91dbca1be0bd SHA-256: b4fd49d7ebab912545740b93728ce9dc50d1b7ecbd3538d77b3cc320a5a82fe5
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs pointing to various PDF files hosted on potentially disposable domains, indicating a link farm designed to distribute malicious content or phish users. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, noting a high number of distinct hosts and UTM parameters, suggesting an attempt to obscure the true malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9947

Heuristics 5

  • 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.
  • 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://phupmirpol.pl/userfiles/file/37000116445.pdf In PDF document text
    • http://kprmk.pl/userfiles/file/77604238883.pdfIn PDF document text
    • http://vietsonplastic.com/uploads/userfiles/file/sazejufelerori.pdfIn PDF document text
    • http://www.auditsi.com/wp-content/plugins/formcraft/file-upload/server/content/files/16131bb55767fc---nufamuwenojuvojovad.pdfIn PDF document text
    • http://hoangduy.vn/vn/files/62627185203.pdfIn PDF document text
    • http://aloisiquadri.it/userfiles/files/mukotoveli.pdfIn PDF document text
    • http://www.atccs3.it/atccs3/fckeditor/editor/ckfinder/userfiles/files/tebomupafajavipowi.pdfIn PDF document text
    • http://ampletrekking.com/userfiles/file/71917331815.pdfIn PDF document text
    • https://mbbs.hr/files/kusugatipudadopukifapax.pdfIn PDF document text
    • http://exclusivelimoservice.com/ckfinder/userfiles/files/966637062.pdfIn PDF document text
    • http://mackielaw.net/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/welikiribogoviworak.pdfIn PDF document text
    • http://prograsifkalip.com/files/nekupela.pdfIn PDF document text
    • http://hueide.com/upload/files/15754057038.pdfIn PDF document text
    • https://vayamcs.com/content_files/files/baloxezozagilikubu.pdfIn PDF document text
    • http://businessdevelopmentcenter.pl/uploads/userfiles/files/41340845653.pdfIn PDF document text
    • http://cokhihoangvinh.com/uploads/userfiles/file/noxanixibupodegexutasime.pdfIn PDF document text
    • http://edbiji.com/uploads/files/20210905141738_805998.pdfIn PDF document text
    • http://ingegnasrl.com/userfiles/files/82017535982.pdfIn PDF document text
    • http://eltprof.ru/userfiles/file/11821623414.pdfIn PDF document text
    • http://katachizu.com/img/news/files/10984095071.pdfIn PDF document text
    • http://salkim.com/userfiles/file/riwijorimukibimuvogobi.pdfIn PDF document text
    • http://balletpanov.com/uploads/files/lobijapemamugagewewutu.pdfIn PDF document text
    • http://oshcongregation.com/userfiles/file/keresizafidagidogi.pdfIn PDF document text
    • http://promocode.lu/userfiles/files/fugilalebod.pdfIn PDF document text
    • http://bdsps.org/slbdavbatala/userfiles/file/fagafoteluzixajeti.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3vuEKuznOb8/uplcv?utm_term=wordly+wise+book+8+lesson+7+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_off0000b597.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB597 15508 bytes
SHA-256: dbc05526d77f6cb9b195ac47ad1d98b79b904177e50d1d5f2aa6152b3f734c58
font_01_sfnt_off0000dd17.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD17 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f52e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF52E 10912 bytes
SHA-256: 7bdfa451276f91a6b951c10db168936085e1e53b9bde8920fbff210ff3dc40ed