Malicious PDF — malware analysis report

Static analysis result for SHA-256 21414ac17a79d3bc…

MALICIOUS

PDF

75.3 KB Created: 2021-09-18 09:26:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: ae36a11fcdf82a1867596d4381836717 SHA-1: 9861a142e3f5b5403d876e831649869dc2601d37 SHA-256: 21414ac17a79d3bc76936e0fb6e6cc2c52baf8f1d9918389e80e22f0d891403f
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected as a malicious PDF by ClamAV and an ML classifier, with high-severity heuristics indicating random and disposable URLs. The PDF contains numerous links to external websites, suggesting it acts as a lure to phishing or malware download sites. While no scripts were explicitly extracted, the presence of PDF_RANDOM_URL_LINK and PDF_SEO_DISPOSABLE_LINK_FARM heuristics strongly suggests an attempt to distribute malicious content or phish users.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://krisoc.ru/uplcv?utm_term=naruto+shippuden+1080p PDF link annotation
    • https://kaptenhoki.org/contents/files/lavezekaginizal.pdfIn PDF document text
    • https://ruxthai.com/ckfinder/userfiles/files/xerotorarevozutiva.pdfIn PDF document text
    • http://foto-recepty.sk/images/fotky/62219274106.pdfIn PDF document text
    • http://mardeestilos.es/fotos/file/597160237.pdfIn PDF document text
    • http://mcenterdk.ru/fck_editor_files/files/79543086949.pdfIn PDF document text
    • http://lnv-cnc.gr/userfiles/file/57669737948.pdfIn PDF document text
    • http://namlinhchisapa.com/userfiles/image/file/zerufi.pdfIn PDF document text
    • https://101doctor.com/uploads/ckfiles/files/613f5bfe3cf1d.pdfIn PDF document text
    • http://mrspk.com/ckfinder/userfiles/files/37772918017.pdfIn PDF document text
    • http://pincailight.com/zk/UploadFile/file/2021090817262373499.pdfIn PDF document text
    • http://candientuvibra.com/images/file/93813669544.pdfIn PDF document text
    • http://chelseacarpet.com/ckfinder/userfiles/uploads/nigafe.pdfIn PDF document text
    • https://actor-conseil.com/files/file/jivaliletipaxuwatexijuta.pdfIn PDF document text
    • http://www.pics4us.de/userfiles/file/72987005394.pdfIn PDF document text
    • http://www.sunarnuricomuisvealisverismerkezi.com/wp-content/plugins/super-forms/uploads/php/files/lo4tc8ld05ecsm4f61ichpnbc4/88403358926.pdfIn PDF document text
    • https://alternativecarrepair.com/userfiles/file/15963768930.pdfIn PDF document text
    • http://werkkledingverkoop.nl/images/docman/files/92851733415.pdfIn PDF document text
    • http://99hospitalitygroup.com/ckfinder/userfiles/files/mapodebufowenudega.pdfIn PDF document text
    • https://gift-edu.ru/wp-content/plugins/super-forms/uploads/php/files/b06b5f7dd0cf8a6e63a806ae00fff45c/ludidora.pdfIn PDF document text
    • http://dnt-mayak.ru/content/File/mudab.pdfIn PDF document text
    • http://biemmecommerciale.eu/userfiles/files/14377900793.pdfIn PDF document text
    • http://orvositudasbazis.eu/images/upload/file/26261952483.pdfIn PDF document text
    • https://sitpchemcieszyn.pl/_sitpchem/file/51353108113.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_off0000c0d9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC0D9 10904 bytes
SHA-256: 6667a14c419064ddb701607648f4b01a09982112d6ace3d2320dd456bcb590c8
font_01_sfnt_off0000da13.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA13 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f225.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF225 17408 bytes
SHA-256: 1a3a40aa5c483fc4fa937eefce594b571fed6be6a24c5e81cc1dab206345782c