Malicious PDF — malware analysis report

Static analysis result for SHA-256 850536e8ccf5828f…

MALICIOUS

PDF

92.1 KB Created: 2021-09-21 23:01:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 176bf810d46c44f5ce4642d174b68463 SHA-1: 465781a7a1d39df5bd88c26ed365b78ced150f9b SHA-256: 850536e8ccf5828f255ff4a773006a8b278785dc8065257e6d8b0d8b476da97e
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution T1059.007 JavaScript

This PDF file was flagged by multiple heuristics, including a critical ClamAV detection and an ML classifier indicating maliciousness. The presence of a 'Security software disable instruction' heuristic strongly suggests an attempt to bypass defenses. While no scripts were explicitly extracted, the PDF structure and the nature of the heuristics point towards a phishing or exploit delivery mechanism, likely involving embedded JavaScript to achieve its malicious goals.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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
  • Security software disable instruction high SE_SECURITY_BYPASS
    Document instructs the user to disable antivirus or security software — unusual for ordinary documents and high-risk in an unsolicited file
  • 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://duongthuy.net/userfiles/file/81655842688.pdf In PDF document text
    • http://dr-temt.ru/images/file/3586096847.pdfIn PDF document text
    • http://ontheedgeofnow.com/wp-content/plugins/formcraft/file-upload/server/content/files/16130c900109e2---29182149593.pdfIn PDF document text
    • http://russkiivopros.com/images/FCKeditor/file/pijawelirenezakarugeluvov.pdfIn PDF document text
    • http://zuche0551.com/upload/file/12483533082.pdfIn PDF document text
    • http://www.skk.com.hk/admin/ckfinder/userfiles/files/65232509782.pdfIn PDF document text
    • http://imosa.asia/uploads/files/202109040513498987.pdfIn PDF document text
    • http://feuerwehr-mittenwalde.de/mediathek/files/miniravapi.pdfIn PDF document text
    • http://dsagco.com/Upload/file/26750341044.pdfIn PDF document text
    • http://abwmechanicsville.com/uploads/files/72552190283.pdfIn PDF document text
    • http://okna-stv.ru/userfiles/files/96634628087.pdfIn PDF document text
    • http://www.hkimm.hk/_bin/ckfinder/userfiles/files/lojelij.pdfIn PDF document text
    • https://takarasushimn.com/userfiles/files/kimewewofoxe.pdfIn PDF document text
    • https://wyslijpaczki.pl/app/webroot/files/userfiles/file/81726238008.pdfIn PDF document text
    • http://mayjack.com/upload/files/72540660785.pdfIn PDF document text
    • https://www.kiemtoandongnghi.com/public/plugins/ckfinder/userfiles/files/78144641124.pdfIn PDF document text
    • http://ukkies.be/userfiles/file/talejenupulumimaketebupu.pdfIn PDF document text
    • http://bestbelly.org/content/files/files/sofawamonoxoma.pdfIn PDF document text
    • https://mountainbrookbuilders.com/home/mountain/public_html/ckfinder/userfiles/files/76701794494.pdfIn PDF document text
    • http://sea-cruise.ru/ckfinder/userfiles/files/29121343273.pdfIn PDF document text
    • https://xedulichhaiphong.vn/images/news/files/nepaxirefabazen.pdfIn PDF document text
    • https://istanajpdua.com/contents/files/buvak.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/fzgW7-mxBc0/uplcv?utm_term=smartgaga+1.1+setupPDF 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_off000102c1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x102C1 10528 bytes
SHA-256: 31413ccfe0d18686a973c08b2ae6627dd5f1b850b141dd83e4aebe03ed342332
font_01_sfnt_off00011acf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11ACF 18128 bytes
SHA-256: 6d9d0242e45dd9759f5c33ddfa0ed6e06390d9955705facb4aaf01383f90a99f
font_02_sfnt_off00014a5e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14A5E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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