Malicious PDF — malware analysis report

Static analysis result for SHA-256 8421f1be2b3c6661…

MALICIOUS

PDF

104.4 KB Created: 2021-09-04 01:54:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: ab03e6cb892a69a4320554d6bc9eb55e SHA-1: e7bec48521e24b9572887cd9897bedc986089dea SHA-256: 8421f1be2b3c6661c8c2609371c10c5296e32576e1e5b36bff421a0cd4b2ae6d
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF was flagged by ML classifiers and ClamAV as malicious, indicating a phishing or trojan distribution attempt. It contains numerous links to external websites, many of which are hosted on compromised CMS platforms or disposable domains, suggesting a link farm designed to redirect users to malicious content. The presence of embedded URLs and the nature of the heuristics strongly suggest this document is part of a phishing campaign, likely using spearphishing attachments as the initial access vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9966

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://nsck-cykelmotion.dk/ckfinder/userfiles/files/wirog.pdf In PDF document text
    • http://icsbc.ru/fuploader//file/91140716469.pdfIn PDF document text
    • http://hcvitamin.com/webroot/img/files/83912434174.pdfIn PDF document text
    • http://stacjaregeneracja.pl/userfiles/file/86588317785.pdfIn PDF document text
    • https://igk-lilienthal.de/downloads/difewoxamagenowapivote.pdfIn PDF document text
    • https://thesmithgrouphouston.com/wp-content/plugins/super-forms/uploads/php/files/06a9d4879530c633b24cc76655e8e832/solakasasegexiji.pdfIn PDF document text
    • http://www.hptindia.com/wp-content/plugins/formcraft/file-upload/server/content/files/160728f0c2615e---jamorofikamigubudinaw.pdfIn PDF document text
    • https://bestcoloringpages.com/userfiles/file/xijebiketazu.pdfIn PDF document text
    • http://eng.sut.ac.th/tce/2016/administrator/ckfinder/userfiles/files/zavubepakulalaligeniju.pdfIn PDF document text
    • http://prociweb.hu/sites/files/file/vifis.pdfIn PDF document text
    • http://pitneyclan.com/clients/c/c7/c7afcfad87c307b096642b2e35f52d25/File/tuxerofu.pdfIn PDF document text
    • http://chapmanhighschoolclassof1968.com/clients/c/cb/cb1fed5110c07f199f416a264ee6943c/File/93789606990.pdfIn PDF document text
    • https://betonwerkendejonge.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16076586a15f6e---12049792393.pdfIn PDF document text
    • https://fiscalonline.ro/app/webroot/files/userfiles/files/pakojojugizagum.pdfIn PDF document text
    • http://altaprecision.com/userfiles/file/67463448815.pdfIn PDF document text
    • http://kaplanpm.com/wp-content/plugins/formcraft/file-upload/server/content/files/16070bc34dee54---xenenarelufibenebaroku.pdfIn PDF document text
    • http://grappin-annat-como.com/userfiles/grappin-annat-como.com/file/gizexeguxitegaparubowexug.pdfIn PDF document text
    • https://www.grandiosa.is/wp-content/plugins/super-forms/uploads/php/files/5d6iatg7b464dpne4s5bsibij1/56594393488.pdfIn PDF document text
    • https://mosaicopeoplecorporation.com/ckfinder/userfiles/files/rodufanox.pdfIn PDF document text
    • http://thestarbusan.com/FileData/ckfinder/files/20210714_74F996FE4504D623.pdfIn PDF document text
    • https://my-natural-style.net/upload/files/43705480657.pdfIn PDF document text
    • http://marcth.pl/media/fck/file/vexizewetitok.pdfIn PDF document text
    • https://victory-agency.com/wp-content/plugins/formcraft/file-upload/server/content/files/160988276b9945---5363441838.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/fzgW7-mxBc0/uplcv?utm_term=mastitis+in+dairy+cows+pdfPDF 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_off00013620.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13620 17548 bytes
SHA-256: 5c1625e484140f0daee645984cd523b1d030b0df7367e06f9f4aedcdecd8ae86
font_01_sfnt_off0001635f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1635F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00017b76.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x17B76 10628 bytes
SHA-256: d501d2df38d96bf7b649bb7715b05afc8a9aba84fd636c067acaf62118142087

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