Malicious PDF — malware analysis report

Static analysis result for SHA-256 51f7df35691d25b2…

MALICIOUS

PDF

91.8 KB Created: 2021-09-02 23:44:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 2a47f589ebb36a0dfe03910fa608e014 SHA-1: 43311c08a1ef76e9a99b3025b4bb14d2bcf47eb7 SHA-256: 51f7df35691d25b2dfae142fda616d2a54ee6fbbcf45bde26a12bc091f98f918
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a link farm pointing to multiple compromised WordPress sites and disposable hosting, indicating a phishing or malware distribution attempt. The ML classifier and ClamAV detection strongly suggest malicious intent. Although no scripts were explicitly extracted, the PDF structure and embedded URLs are indicative of a malicious document designed to lure users to external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9937

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://crysiq.ru/uplcv?utm_term=organisational+development+mba+notes+pdf PDF link annotation
    • http://electronicaindex.nl/images/uploads/73938844478.pdfIn PDF document text
    • http://herfon-machinery.com/images/ckfinder/files/20210722174709.pdfIn PDF document text
    • https://motionslam.com/wp-content/plugins/super-forms/uploads/php/files/4c4372cc6a7d18481c085fc4d8feb8bb/nuwexozi.pdfIn PDF document text
    • http://chinalabware.es/d/files/sajosozigibufigebigemozer.pdfIn PDF document text
    • https://webtechnocrats.com/upload/file/tatagobubevegowarakuw.pdfIn PDF document text
    • https://apexforestservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/16092a14f71025---18701143788.pdfIn PDF document text
    • https://patriot.ch/wp-content/plugins/super-forms/uploads/php/files/a5id7ma0rv6091dh05m88g5i5f/28768283131.pdfIn PDF document text
    • https://akdenizokullari.k12.tr/wp-content/plugins/super-forms/uploads/php/files/20vts7cdsaslb2ke3q8jmmrcis/94230063801.pdfIn PDF document text
    • https://immsac.pe/sgi_userfiles/userfiles/files/ladokirolirewoxewu.pdfIn PDF document text
    • https://bodwellassociates.com/wp-content/plugins/super-forms/uploads/php/files/68ca2b9e6763e1c393b3fe9327a25362/18971022980.pdfIn PDF document text
    • http://alexhoffordphotography.com/temp/files/file/69425964544.pdfIn PDF document text
    • https://inchiriereelicoptere.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160a94db233ba7---josijifilan.pdfIn PDF document text
    • http://willtorock.com/wp-content/plugins/formcraft/file-upload/server/content/files/16111a3e6bdae5---gibenetuwo.pdfIn PDF document text
    • https://luyenthitoeic.info/userfiles/file/79845459906.pdfIn PDF document text
    • https://sipsib.ru/wp-content/plugins/super-forms/uploads/php/files/a3ab9b90f42cddbca6955c36f0989233/bumefirodokaregifatu.pdfIn PDF document text
    • http://xn--80akij1ajew.xn--p1ai/wp-content/plugins/formcraft/file-upload/server/content/files/160900ef7ca9a7---99733210322.pdfIn PDF document text
    • http://argra.rs/wp-content/plugins/formcraft/file-upload/server/content/files/160998dfab8097---ronofegivepuvemodedima.pdfIn PDF document text
    • http://unionzglobal.com/ckupload/files/lasaziwovep.pdfIn PDF document text
    • http://www.atrium-tuiles.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607f6fb0581ae---47530092051.pdfIn PDF document text
    • http://szyoujin.com/UploadFile/file/20210828040506486.pdfIn PDF document text
    • http://chokmanee.com/userfiles/file/jenavilogovixedobowifan.pdfIn PDF document text
    • http://honeycontacts.com/uploades/userfiles/file/87664340972.pdfIn PDF document text
    • http://www.onlinetemsilci.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607b897adc4cd---71371799992.pdfIn PDF document text
    • http://optikametuje.cz/userfiles/file/raromogudave.pdfIn PDF document text
    • http://turatabor.hu/media/74152546422.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_off00010376.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10376 17428 bytes
SHA-256: 3f87564856dbfbb8891d0811ad5e8f4aa803d4434b8d449c16566929b9a69246
font_01_sfnt_off00013029.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13029 11072 bytes
SHA-256: 091fa3b5c0bd1fefbe3987966169b9bc727847959f0799c06ecfd874ef87d99f
font_02_sfnt_off00014990.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14990 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1