Malicious PDF — malware analysis report

Static analysis result for SHA-256 81b157cf52726ea0…

MALICIOUS

PDF

71.8 KB Created: 2021-09-13 22:10:34 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: c5adc464dbf514f18d3da13e4412050d SHA-1: 240faf5062cd0238d6c3825c9471497372907dcc SHA-256: 81b157cf52726ea00b548e086ce1083f771acec000f9fc131155e0b6407e9868
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF contains numerous embedded URLs, with one heuristic specifically identifying a link farm on disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. While no scripts were directly extracted, the PDF structure and numerous external links suggest it's designed to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://shengnabei.com/uploadfile/file///2021090112285728.pdf In PDF document text
    • http://malifer.hu/upload/file/koxokunakejagowujidusek.pdfIn PDF document text
    • https://vanchuyenduongsat.vn/upload/files/43088005037.pdfIn PDF document text
    • http://china-miyaco.com/img/file/202196161217.pdfIn PDF document text
    • http://ceresasrl.it/userfiles/files/pabuzebuk.pdfIn PDF document text
    • http://innospectrum.eu/hirlevel/file/2360237706.pdfIn PDF document text
    • https://noihoithanhtuan.com/media/ftp/file/negupirabiko.pdfIn PDF document text
    • https://digbijoynath.in/uploads/userfiles/files/rosuxobatobebipuda.pdfIn PDF document text
    • http://africansafaris-spain.com/FCKeditor/editor/filemanager/connectors/php/connector.php?Command=FileUpload&Type=File&CurrentFolder=%2Ffile/reviferegugenunagamu.pdfIn PDF document text
    • https://kar360.com/resimler/files/vukuzumovukabixufogabaw.pdfIn PDF document text
    • http://firmen-bekleidung.at/userfiles/file/92018880995.pdfIn PDF document text
    • https://binarbaidservices.com/public_html/userfiles/file/dituboziwufafa.pdfIn PDF document text
    • https://agrotehholding.ru/wp-content/plugins/super-forms/uploads/php/files/c0cb1be1bbea14d97944e67db4f16002/76810763943.pdfIn PDF document text
    • http://qbcar.ru/ckfinder/userfiles/files/babuliviwurewexo.pdfIn PDF document text
    • https://carthink.org/wp-content/plugins/formcraft/file-upload/server/content/files/1613b6c3063c50---dajeseguji.pdfIn PDF document text
    • http://getwealthythisyear.com/ckfinder/userfiles/files/gekitafadudemeroni.pdfIn PDF document text
    • http://delve-cr.com/uploads/vulomizuwitelenuwewu.pdfIn PDF document text
    • http://tks-forever.com/upload/2021/09/09/file/36546969153.pdfIn PDF document text
    • http://gmart-express.com/demo/uploadpic/file/35253545093.pdfIn PDF document text
    • http://justsayhi365.com/uploads/file/tunebefewaxonula.pdfIn PDF document text
    • http://harposwebdesign.nl/app/webroot/files/userfiles/files/gukopamozapabomedu.pdfIn PDF document text
    • http://modernplating.com/userfiles/file/35395714012.pdfIn PDF document text
    • https://viadagio.be/userfiles/file/25262833659.pdfIn PDF document text
    • http://sk4education.com/ckfinder/userfiles/files/5410094459.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/PmAiG5ZyT-k/uplcv?utm_term=miraculous+shanghai+full+movie+englishPDF 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_off0000b552.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB552 16552 bytes
SHA-256: 1646782bcc0cfe7abe57c292f95756c68f5e7b4d6cc086784aff923a7e3fd446
font_01_sfnt_off0000e042.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE042 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f859.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF859 10844 bytes
SHA-256: 5fe472510ceea99611675fbf72d8a891fab7cc0778b23fcc1a3fa1debce04a5e