Malicious PDF — malware analysis report

Static analysis result for SHA-256 b6524832e2897bd8…

MALICIOUS

PDF

76.8 KB Created: 2021-06-11 07:52:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-27
MD5: 0b173f012ca1da1be390f9dedb1b6a26 SHA-1: 129ae9a2d3e1874373a47db204040835817a154f SHA-256: b6524832e2897bd8e6097cd210c97ef1cd5819779c06e61e44ae4feada0556ef
156 Risk Score

Malware Insights

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

The sample is a PDF file detected as malicious by ClamAV and an ML classifier. It contains numerous links to compromised WordPress sites and disposable hosting, suggesting a link farm used for phishing or malware distribution. The document body, though heavily obfuscated, contains metadata indicating it was generated by wkhtmltopdf, and the presence of embedded URLs points towards an attempt to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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 farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://pistant.ru/uplcv?utm_term=canine+dental+chart+pdf PDF link annotation
    • https://profbuhotchet.ru/wp-content/plugins/super-forms/uploads/php/files/ff435c268848ee28552f12f3b935a6e7/tizenubavolirikijuzeg.pdfIn PDF document text
    • http://www.ddd-iasi.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160a9ed8cf349d---61955203150.pdfIn PDF document text
    • https://rockyshairsalon.com/wp-content/plugins/super-forms/uploads/php/files/7so7a8s9i5ln0slbblrunddshb/bevun.pdfIn PDF document text
    • http://oneself.pro/wp-content/plugins/formcraft/file-upload/server/content/files/160bdeddf21cd7---39451616267.pdfIn PDF document text
    • https://www.baptistenhardenberg.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160a64cba53926---13514386211.pdfIn PDF document text
    • https://cutletsmeat.com/wp-content/plugins/formcraft/file-upload/server/content/files/16070fdb1b294c---wigojirib.pdfIn PDF document text
    • https://www.alongsideasia.com/wp-content/plugins/super-forms/uploads/php/files/d5eead3fe9a47bad17b5395ec8ed04b7/borigupit.pdfIn PDF document text
    • http://clingac.com/d/files/jaraposike.pdfIn PDF document text
    • https://shining4u.com/wp-content/plugins/super-forms/uploads/php/files/274c35fdd37599fad3f9a98ee100c811/62528193700.pdfIn PDF document text
    • https://teenvolunteer.org/wp-content/plugins/super-forms/uploads/php/files/2a56be50f59c5a101b22653b49a1d66f/moretunoxudururawumitilal.pdfIn PDF document text
    • https://idfusionllc.com/wp-content/plugins/super-forms/uploads/php/files/fca804974691c2a951664eaab1ec8e71/fojeregutot.pdfIn PDF document text
    • https://www.inter-tube.co.uk/wp-content/plugins/super-forms/uploads/php/files/517fd0d2a18b945d73c0775dc738f69e/86731883030.pdfIn PDF document text
    • http://mirembeestate.co.ug/wp-content/plugins/formcraft/file-upload/server/content/files/160793ae43ce27---45944461806.pdfIn PDF document text
    • http://warraichmeats.com/wp-content/plugins/formcraft/file-upload/server/content/files/16078b78a9e78e---77930468695.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f266.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF266 4968 bytes
SHA-256: 42cbca01e8d70677edcbe8c0ac11375ec340943d3011f256d10d1ae93f6b7dc5
font_01_sfnt_off00010343.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10343 10476 bytes
SHA-256: bb43681dadd9a2610b85bbd56a4eb37857bd61a1da41f68927acf120f5eabb4f