Malicious PDF — malware analysis report

Static analysis result for SHA-256 658f6f69cadbbf16…

MALICIOUS

PDF

83.6 KB Created: 2021-09-22 18:16:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: a435ea71b4d029dd0da45b4f9ad498c0 SHA-1: 545f207327a4bedf79f741be9ac8673d182e1df8 SHA-256: 658f6f69cadbbf1699e7c36ab2032fc63e7d10569ad4088276f64c6d42e123bd
166 Risk Score

Malware Insights

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

The PDF contains numerous links to external PDF files hosted on a variety of domains, many of which appear to be low-reputation or disposable. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' strongly suggests this is a link farm designed to distribute malicious content. The ML classifier and ClamAV detection further confirm its malicious nature, likely serving as a lure for phishing or to download further malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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
  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://catamma.ru/uplcv?utm_term=all+types+of+lines PDF link annotation
    • http://gesht.ru/admin/ckfinder/userfiles/files/kokobavasariwavirizo.pdfIn PDF document text
    • http://voijin.com/userfiles/files/zuvafoletumexakijewaj.pdfIn PDF document text
    • http://mastervin.ru/files/file/jiwevewemati.pdfIn PDF document text
    • http://cgpharma.in/cote_dor_import/admin/ckfinder/userfiles/files/volesi.pdfIn PDF document text
    • http://inbond-cn.com/userfiles/file/kiwenupixasa.pdfIn PDF document text
    • http://kiszelyugyvediiroda.hu/docs/file/gazenesabisozuvegube.pdfIn PDF document text
    • http://ekopaczka.pl/imgbrama/files/29596516240.pdfIn PDF document text
    • https://aydin-elektrik.com/resimler/files/34715914932.pdfIn PDF document text
    • http://yesilderecine.com/admin/editor_resim/file/54014494570.pdfIn PDF document text
    • https://childrencareandliteracysociety.org/userfiles/files/zejolejuriwuv.pdfIn PDF document text
    • http://aimecostruzioni.it/userfiles/files/21659901462.pdfIn PDF document text
    • http://kondicionery-domodedovo.ru/upload_picture/file/25225953912.pdfIn PDF document text
    • http://liavanhaeringen.nl/userfiles/files/69002025135.pdfIn PDF document text
    • http://viethanit.vn/hinhanh/file/9256021235.pdfIn PDF document text
    • http://drxzhang.com/userfiles/file/wojet.pdfIn PDF document text
    • http://vhshf.de/File/zogemarukaduvimoz.pdfIn PDF document text
    • http://www.sudaff.com/pics/file/24664277593.pdfIn PDF document text
    • https://ibshospitals.com/userfiles/file/nelixijidoxaxuzeme.pdfIn PDF document text
    • http://www.norestim.ro/wp-content/plugins/formcraft/file-upload/server/content/files/161303315a533c---fazedijazuwitaref.pdfIn PDF document text
    • http://www.vnos.vn/app/webroot/uploads/files/66479874740.pdfIn PDF document text
    • https://xlquality.com/userfiles/file/94552494326.pdfIn PDF document text
    • http://psychologadamczak.pl/userfiles/file/kuzevonokufoxapirudore.pdfIn PDF document text
    • https://businesslife.com/content/files/pepodatujexuxudijubolekit.pdfIn PDF document text
    • https://gservicepz.com/wp-content/plugins/super-forms/uploads/php/files/4d1422af0f8c86e1a14b51a7f588c7ff/81358209251.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_off0000e466.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE466 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fc78.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC78 17816 bytes
SHA-256: b9fd4ca07db79124022c1cf7a9f3470d97e69a74eb5526fc8b86777a4a49982e
font_02_sfnt_off000129e5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x129E5 10184 bytes
SHA-256: b9c6b535af7654e798dd74564b3e5bccdc3050a4abb627e0917052070a3ec93b