Malicious PDF — malware analysis report

Static analysis result for SHA-256 bd435768ce297e6a…

MALICIOUS

PDF

89.4 KB Created: 2021-09-19 13:21:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-21
MD5: 3c0ff727abe3774eb15ec46ec786c38e SHA-1: 3f065b6fda8bb0f2b23124b83f08203a4bea9008 SHA-256: bd435768ce297e6adb21d4528743988fae0bc503144d8c9d8e6fed2227422d01
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs pointing to external sites, many of which are structured as link farms on disposable hosting. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not meant for direct user consumption but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 5

  • 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.
  • 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=brothers+movie+watch+online+filmywap PDF link annotation
    • https://medtek.vn/storage/file/gaxitinuwov.pdfIn PDF document text
    • http://sayarbobinaj.com/file/14400743783.pdfIn PDF document text
    • https://roshnaai.com/ckfinder/userfiles/files/bokadukofalegaludufenab.pdfIn PDF document text
    • http://twfindia.in/userfiles/files/55392357768.pdfIn PDF document text
    • http://choinka4x4.org/cms/files/file/borefiniwoxapumefi.pdfIn PDF document text
    • http://abwvictory.com/uploads/files/39281108356.pdfIn PDF document text
    • https://www.tcf.gov.tr/ckfinder/userfiles/files/kafalugesopumaxiwefoju.pdfIn PDF document text
    • https://www.limratechnologies.net/wp-content/plugins/formcraft/file-upload/server/content/files/1613b7dbc39f12---25815461984.pdfIn PDF document text
    • https://xulynuocphangiathinh.vn/images/pic/file/44982279350.pdfIn PDF document text
    • http://webcertain.net/contentupload/fckeditorUploads/organization_/file/dokagukotosida.pdfIn PDF document text
    • http://thingsantiquesla.com/userfiles/files/81327885117.pdfIn PDF document text
    • http://seo-methodes.com/userfiles/file/59334500885.pdfIn PDF document text
    • https://lingchuanfloor.com/app/webroot/userfiles/files/jininox.pdfIn PDF document text
    • http://imapbook.com/fckeditor/editor/filemanager/connectors/php/userfiles/file/41231369793.pdfIn PDF document text
    • http://salman-group.com/userfiles/file/tidawigonemubuvekanokogaj.pdfIn PDF document text
    • https://varbackaforskola.se/ckfinder/userfiles/files/muneloxeborelabudewisosug.pdfIn PDF document text
    • https://idfusionllc.com/wp-content/plugins/super-forms/uploads/php/files/ba588549a6282e800d8826847ad04736/41982787814.pdfIn PDF document text
    • https://daqing-jewelry.com/uploads/files/202109012327228344.pdfIn PDF document text
    • https://grdr.org/paidel/ckfinder/userfiles/files/45469092621.pdfIn PDF document text
    • https://matao.ro/app/webroot/files/userfiles/files/78430717453.pdfIn PDF document text
    • https://kipass.fr/userfiles/file/gakos.pdfIn PDF document text
    • http://antropolog.ru/userfiles/file/pebapi.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_off0000f881.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF881 17596 bytes
SHA-256: 18476b83c8fcb5aa4e1d1a37f2da05062b13372855a420e72c035a621e8ca112
font_01_sfnt_off000125c4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x125C4 11064 bytes
SHA-256: 1ec143a1112725b161426eb422545568de41cec76554c5172c4bda9fd90e0af8
font_02_sfnt_off00013f84.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13F84 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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