Malicious PDF — malware analysis report

Static analysis result for SHA-256 8a09a36795033c11…

MALICIOUS

PDF

83.8 KB Created: 2021-09-20 18:17:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 21d39576dfad77cefdcc4a8a9fce6845 SHA-1: 7a32ba2ee9dab1626247fb5f6937cee8425933bf SHA-256: 8a09a36795033c118b91d16302001151e6c846410741d5a43b3d79bc5394aa5c
126 Risk Score

Malware Insights

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

The file was detected as a malicious PDF by ClamAV and an ML classifier. Heuristics indicate it functions as a link farm, with numerous distinct hosts and UTM parameters, suggesting a phishing or malware distribution attempt. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic specifically flags this behavior. No scripts were extracted, and the document body was unreadable, but the overall structure and URL analysis strongly suggest a malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 https://artgreen.vn/attachment/files/40061269162.pdf In PDF document text
    • http://www.cuerpomenteyespiritu.es/wp-content/plugins/formcraft/file-upload/server/content/files/1613847c395546---29169750769.pdfIn PDF document text
    • http://reafamily.lt/ckfinder/userfiles/files/86621449878.pdfIn PDF document text
    • https://k-barrierfree.com/FileData/ckfinder/files/20210903_9F8F77E51F4B33E6.pdfIn PDF document text
    • http://agro-partner.com/Image/files/21936482997.pdfIn PDF document text
    • http://burbank.kopanramen.com/uploads/files/49387558843.pdfIn PDF document text
    • http://maraulsan.com/ckfinder/userfiles/files/supogadubuwonewakoxiregud.pdfIn PDF document text
    • http://medica-brno.com/files/padusador.pdfIn PDF document text
    • http://stefani.cz/fck/file/medoj.pdfIn PDF document text
    • http://mictrogiang.com/userfiles/files/31860197412.pdfIn PDF document text
    • http://dae-young.kr/upload/fckeditor/file/vifeta.pdfIn PDF document text
    • https://atlas-consulting.ro/fckeditor/fisiere/file/nozogejatuli.pdfIn PDF document text
    • http://madurastones.com/userfiles/file/20700381544.pdfIn PDF document text
    • http://www.asiacoservice.com/file/files/459869257.pdfIn PDF document text
    • http://kelvista.lt/images/files/94367725524.pdfIn PDF document text
    • https://www.burnat-provins.ch/ck/ckfinder/userfiles/files/74696379945.pdfIn PDF document text
    • https://afayl.com/userfiles/file/gexuvoraruk.pdfIn PDF document text
    • http://didongsinhvien.com/upload/files/noxedeziwoguju.pdfIn PDF document text
    • http://redskap.ru/userfiles/file/sogogevaruzizi.pdfIn PDF document text
    • http://marktoby.com/akram/know_news/admin/userfiles/file/47020308321.pdfIn PDF document text
    • https://hotnewsmd.deca.md/upload/userfiles/files/29036178764.pdfIn PDF document text
    • https://okazdedziecko.pl/_files/Media/file/filidepupa.pdfIn PDF document text
    • http://topup-fight.com/ckfinder/userfiles/files/92275316826.pdfIn PDF document text
    • https://nicemexico.net/wp-content/plugins/formcraft/file-upload/server/content/files/1614471f55e22c---mekotutefixek.pdfIn PDF document text
    • https://www.zochrot.org/ckfinder/userfiles/files/8282398551.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BkSY9tpko7c/uplcv?utm_term=infinity+armor+minecraft+pe+mod+downloadPDF 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_off0000dfa8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDFA8 18692 bytes
SHA-256: b485636d1fb7548cad73f4900dd9c6b109d19be645ae346bed362643f7b49d8f
font_01_sfnt_off00011091.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11091 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000128a8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x128A8 10764 bytes
SHA-256: 3742471dfa7d9aa26e1f7da64e9f90295a4eabd0465d6d0833024ef404c58ff9