Malicious PDF — malware analysis report

Static analysis result for SHA-256 39b79e46b9bd598e…

MALICIOUS

PDF

96.5 KB Created: 2021-09-03 08:51:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 21e6646200069699cfd82e29402b4cb3 SHA-1: 95b82f89252591c45fbb3ffc428604b72c07850b SHA-256: 39b79e46b9bd598edf85dbf77b08a2162aecf39498385ee59bf22c7bbed98f2a
156 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics and a machine learning classifier as malicious, with ClamAV identifying it as a phishing trojan. It contains numerous embedded URLs, many pointing to compromised WordPress sites, and one specifically uses a UTM term suggesting a lure. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, indicating it's not meant for direct user consumption but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9957

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 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://huntic.ru/uplcv?utm_term=kenwood+bluetooth+radio+manual PDF link annotation
    • https://loskutova.site/wp-content/plugins/super-forms/uploads/php/files/0ac077d53c45666be26a1b64136267da/vewaneb.pdfIn PDF document text
    • https://paloaltospeakerseries.com/wp-content/plugins/super-forms/uploads/php/files/67d766d346af7fd395fae8bdd866c4a3/50723322308.pdfIn PDF document text
    • http://bulgankhangai.mn/userfiles/files/biziwo.pdfIn PDF document text
    • https://www.rowtheerne.com/wp-content/plugins/super-forms/uploads/php/files/2436f61317b5a8bce8ecc5b3275a5e10/39496441264.pdfIn PDF document text
    • http://colescastle.com/clients/875019/File/7775764065.pdfIn PDF document text
    • http://www.peritaonline.es/ckfinder/userfiles/files/40238857198.pdfIn PDF document text
    • http://brothersaluminium.com.np/wp-content/plugins/formcraft/file-upload/server/content/files/1609c79ec70d9b---7252335422.pdfIn PDF document text
    • http://prochem.vn/images/uploads/files/dikinotix.pdfIn PDF document text
    • http://suurelepa.ee/data/file/34565606485.pdfIn PDF document text
    • http://cleanking.net/userData/board/file/fanunexavagogozibofawojis.pdfIn PDF document text
    • http://motivationandmomentum.net/ci/userfiles/files/tadel.pdfIn PDF document text
    • http://homeopathyhongkong.cn/files/36638376761.pdfIn PDF document text
    • http://diversecityuk.com/userfiles/file/xijojaji.pdfIn PDF document text
    • https://greenvalleykerala.com/ckfinder/userfiles/files/95492526517.pdfIn PDF document text
    • https://parisautotravel.com/wp-content/plugins/super-forms/uploads/php/files/f2h6pneq8b651f0oabbkigohn5/21647248433.pdfIn PDF document text
    • https://www.beadvised.co.uk/wp-content/plugins/super-forms/uploads/php/files/56bfce9627641dba5db33107508dbaf7/pabuwesidimelitiritip.pdfIn PDF document text
    • http://brodart01.com/wp-content/plugins/super-forms/uploads/php/files/jfstr6835sg6iqkgkqh8nqab7b/jirinipimibunuv.pdfIn PDF document text
    • http://jeugdopdewetenschapsagenda.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160aea49f3e7c1---ginigokip.pdfIn PDF document text
    • http://nc2e.fr/wp-content/plugins/formcraft/file-upload/server/content/files/16084d28772160---rezazulel.pdfIn PDF document text
    • http://przedszkolenisko.pl/userfiles/file/jolus.pdfIn PDF document text
    • http://nelly-design.ru/upload/files/rotunuxu.pdfIn PDF document text
    • https://hashtag.school/userfiles/file/disopem.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_off00011505.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11505 18188 bytes
SHA-256: f4afa3e50c0768ef9747d4d39143a3aac832d250250349fb0f66b7873e4a744c
font_01_sfnt_off00014491.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14491 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00015ca8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15CA8 10660 bytes
SHA-256: a21b603aa331f100714d5b52b4f64566133c8e626bf67198f284d8a94f5e1833

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