Malicious PDF — malware analysis report

Static analysis result for SHA-256 73b3384cb5ee7aa0…

MALICIOUS

PDF

82.4 KB Created: 2021-09-18 21:54:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 8137069ecb55630ed0ba41190042911a SHA-1: d3a873db8fd9a06830cb4401ccefc848fe792c68 SHA-256: 73b3384cb5ee7aa00bf467791313f67eafc119cceba8232af951f1d163ebd6a7
134 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file detected as malicious by ClamAV and an ML classifier. It contains embedded JavaScript and numerous external URIs, many of which are hosted on disposable domains, suggesting a link farm or phishing lure. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a high likelihood of malicious intent, possibly to redirect users to exploit kits or phishing pages.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9846

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
  • 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 http://chothuexeninhbinh.net/data/dulieu/files/kixoz.pdf In PDF document text
    • http://zetrade.cz/userfiles/file/61143540335.pdfIn PDF document text
    • http://mea-travel.pl/userfiles/file/9776472972.pdfIn PDF document text
    • https://eingangrad.ch/userfiles/files/13474350315.pdfIn PDF document text
    • http://shinhwajudan.com/userData/board/file/38757908453.pdfIn PDF document text
    • https://contemporaryteas.in/admin/uploads/file/nutefepe.pdfIn PDF document text
    • http://gattoneva.pl/pages/userfiles/file/mapesadukefijozumaraz.pdfIn PDF document text
    • http://flex-link.cn/uploadfiles/files/80866919384.pdfIn PDF document text
    • http://degeninhotel.ru/admin/ckfinder/userfiles/files/limatarobemixu.pdfIn PDF document text
    • http://scea.edu.mn/ckfinder/userfiles/files/sozuv.pdfIn PDF document text
    • https://konferencii.ru/js/ckfinder/userfiles/files/81865770239.pdfIn PDF document text
    • http://studiophotosfashion.it/userfiles/files/55386288713.pdfIn PDF document text
    • http://hai-bi.com/uploads/files/202109170449126173.pdfIn PDF document text
    • http://www.performhabitat.fr/bundles/astadmin/js/ckfinder/userfiles/files/60949433886.pdfIn PDF document text
    • http://bagumul.com/file_upload/spaw_upload/file/20210913205042.pdfIn PDF document text
    • http://aktifimmo.lu/userfiles/files/fumobokunex.pdfIn PDF document text
    • http://jdjcnc.com/upfolder/e/files/20210907050407.pdfIn PDF document text
    • http://kamkmori.cz/ckfinder/userfiles/files/sawosebatus.pdfIn PDF document text
    • https://lesura.net/userfiles/file/81530133376.pdfIn PDF document text
    • http://kythuatviet.vn/uploads/userfiles/file/laferafokig.pdfIn PDF document text
    • http://sanraimundo.cl/dyn/uploads/file/51409455560.pdfIn PDF document text
    • http://reguitti-engineering.it/userfiles/files/30699609924.pdfIn PDF document text
    • http://kaplanpm.com/wp-content/plugins/formcraft/file-upload/server/content/files/161349aee03d3d---jugedawiwajafus.pdfIn PDF document text
    • http://cutskytools.com/d/files/71817860951.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=airscreen+pro+mod+apkPDF link annotation
    • http://pro.ovh.net/~tribuene/images/banque/file/xaxepipopixuron.pdfIn PDF document text
    • http://s292376414.onlinehome.fr/datas/imgmail/file/giwanadun.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_off0000dab8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDAB8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f2ca.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2CA 18612 bytes
SHA-256: fd1419c1375e098347703f485323d9b7f737715821db342f4d9fcc40ba7aedb8
font_02_sfnt_off000123bb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x123BB 10604 bytes
SHA-256: 918b9d092d984d0aa6438d1914fbec36c9e3d2f4042f93fd4d81ff4dc9aa6301