Malicious PDF — malware analysis report

Static analysis result for SHA-256 31bc23adcd490c5c…

MALICIOUS

PDF

87.2 KB Created: 2021-08-06 02:48:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: 3618d9538fc9f5ef27ecb5c75cecabc4 SHA-1: d0b6b8519b5c2620ffca796db25d478e72cc45a4 SHA-256: 31bc23adcd490c5c0f8aed96310a14fea81ce5e126bf12e70e0a9855b78e0bf0
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Several heuristics point to the PDF acting as a link farm, directing users to potentially compromised or malicious websites hosted on disposable domains. While no scripts were explicitly extracted, the PDF structure and embedded URLs suggest it's designed to redirect users, likely as part of a phishing or malware distribution scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://refour.dk/wp-content/plugins/super-forms/uploads/php/files/7bcd31f3656699c58b79ac781bfb459f/41247941216.pdf In PDF document text
    • http://www.iqubz.com/wp-content/plugins/formcraft/file-upload/server/content/files/160703a0203501---diguxokobi.pdfIn PDF document text
    • https://chicagoportablexray.com/wp-content/plugins/formcraft/file-upload/server/content/files/16093c9874ab59---dusifum.pdfIn PDF document text
    • http://rund.cz/UserFiles/File/wuwizobimafegoja.pdfIn PDF document text
    • https://mebelpozakazu.ru/wp-content/plugins/super-forms/uploads/php/files/0955a1aa1f458cd04518eda6a888bb0e/11869892182.pdfIn PDF document text
    • http://simonide.org/userfiles/file/36798429139.pdfIn PDF document text
    • http://congtyvima.com/images/Download/nebavapale.pdfIn PDF document text
    • https://tradingphrases.net/userfiles/files/weboka.pdfIn PDF document text
    • https://lsp.od.ua/wp-content/plugins/super-forms/uploads/php/files/doolfnde838utenblvmf1a3g42/79282923882.pdfIn PDF document text
    • https://sv-fin.ru/wp-content/plugins/super-forms/uploads/php/files/330dcc3f807657a972d56a565856886b/jogaxelazorojit.pdfIn PDF document text
    • https://bishopsalamatkhokhar.org/userfiles/file/vafowadunulupa.pdfIn PDF document text
    • https://freebcard.com/ckfinder/userfiles/files/dapopuku.pdfIn PDF document text
    • https://www.colours-of.com/wp-content/plugins/super-forms/uploads/php/files/6hk59bft3rajplccljdfjg0vlo/tegufelejip.pdfIn PDF document text
    • http://zbigniewrodak.pl/galeria/file/98276173791.pdfIn PDF document text
    • http://mtecommerce.it/public/news/file/25191375350.pdfIn PDF document text
    • https://www.amiunaorchestra.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1607624f4e6f17---rilupileroremu.pdfIn PDF document text
    • https://uleiuri.ro/userfiles/file/2571905541.pdfIn PDF document text
    • https://gabconstruction.com/ckfinder/userfiles/files/juvizafozuwesozub.pdfIn PDF document text
    • https://dcoderesearch.com/uploads/71999870077.pdfIn PDF document text
    • https://www.euroservicemilano.it/wp-content/plugins/formcraft/file-upload/server/content/files/1606f57e02d9ab---muginexa.pdfIn PDF document text
    • http://work4shop.cz/userfiles/file/82857960501.pdfIn PDF document text
    • http://ettermanenterprises.com/ckfinder/userfiles/files/63464907049.pdfIn PDF document text
    • https://webhostmurah.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ad0b43e5a85---gofubuwasa.pdfIn PDF document text
    • http://dansecyr.ca/pdf/file/gulekuxemus.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/DOqCt-cVA4I/uplcv?utm_term=transitive+and+intransitive+verbs+quiz+grade+8PDF 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_off0000ec83.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC83 10940 bytes
SHA-256: 71adfff6d3fc529f44065246bd8cf3615539ec785bd43fef7b12d3da8d1dc26b
font_01_sfnt_off00010594.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10594 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011da6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11DA6 17824 bytes
SHA-256: 554dbd6655dc5c4302f637166ce643de05befdb72fc43853e27e12fa13b854c2

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