Malicious PDF — malware analysis report

Static analysis result for SHA-256 837b5f73d6c57aef…

MALICIOUS

PDF

85.1 KB Created: 2021-09-02 12:14:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: efaaa4835ad2c058a0e80cd5dd63b1ac SHA-1: 8e80cf9f4c027c5feba667cb929fbe078945b05b SHA-256: 837b5f73d6c57aef472b597f081e28ba795fd9c4fbc3033caac567a6abbbd2c7
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF containing embedded JavaScript, which is a common technique for malicious PDFs. It also contains numerous links to external websites, many of which are hosted on compromised WordPress sites, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware delivery through these compromised sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://www.pharmaright.ca/wp-content/plugins/super-forms/uploads/php/files/r0m9g559toqaf9djjj56op5ouq/kuxigikus.pdf In PDF document text
    • http://wabasnb.com/files/fckeditor/file/58848568860e677a23ef4c.pdfIn PDF document text
    • https://jollytime.ru/wp-content/plugins/super-forms/uploads/php/files/049d95c91a17ea2b27c3874bce91d2cb/lakeduwugefe.pdfIn PDF document text
    • http://aristosaigonhotel.vn/uploads/files/sabudolupaxovemol.pdfIn PDF document text
    • http://kaizousha.com/js/upload/files/74961837630.pdfIn PDF document text
    • https://cjsc.se/ckfinder/userfiles/files/65401595710.pdfIn PDF document text
    • http://techniq.ae/admin/uploadfiles/file/dujuf.pdfIn PDF document text
    • http://hzbmsj.net/images/upload/File/doteru.pdfIn PDF document text
    • https://hondamienbac.vn/userfiles/file/ripuxejosabevuxopojegase.pdfIn PDF document text
    • https://www.okcfarmersmarket.com/wp-content/plugins/super-forms/uploads/php/files/a37360943ec34a57360539294f65e213/bonuj.pdfIn PDF document text
    • https://thesmithgrouphouston.com/wp-content/plugins/super-forms/uploads/php/files/3f23d7e57fb38c492562440727bf6df1/13737664316.pdfIn PDF document text
    • http://omgmediatank.com/userfiles/files/vejaz.pdfIn PDF document text
    • http://screen.by/images/file/fevezetewi.pdfIn PDF document text
    • http://schouteninterieurwerk.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160dc7555d0c47---nupevukobe.pdfIn PDF document text
    • https://certifiedmoversinc.com/wp-content/plugins/super-forms/uploads/php/files/5a1343bfc6a2fbdec8acc8f2f0de065d/vomuvonowi.pdfIn PDF document text
    • http://www.madiran-cruduparadis.fr/ckfinder/userfiles/files/25080799975.pdfIn PDF document text
    • https://activepymes.com/pub/file/pimepemozifasedujodawaz.pdfIn PDF document text
    • http://laconchigliacasevacanze.it/userfiles/files/70797707051.pdfIn PDF document text
    • http://sieuthibds.net/images/files/nejigexevebe.pdfIn PDF document text
    • http://jikaramen.com/uploads/files/lojopakafowalejepoxeraju.pdfIn PDF document text
    • http://poorclarescork.ie/images/42543297868.pdfIn PDF document text
    • https://teplitsyoptom.ru/wp-content/plugins/super-forms/uploads/php/files/38f51e1f68cf448774eff7cefafd9794/63083340122.pdfIn PDF document text
    • http://braghieriarchitettura.com/userfiles/files/75703293292.pdfIn PDF document text
    • https://www.hit-education.com/wp-content/plugins/super-forms/uploads/php/files/d9qjt1fn5jbiuavtkcfkk8ub5j/96253406623.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1KS0DP0cxss/uplcv?utm_term=sintomas+de+estenosis+aortica+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_off0000e6a6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE6A6 18584 bytes
SHA-256: d47d8d4d908261062fdb07b7c220a14a151764fd9b62461ddca436704a9446c8
font_01_sfnt_off000115d5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x115D5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012dec.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12DEC 10812 bytes
SHA-256: 66acbd444b424402fdadebd206ecb67a24679eb5a94d902f3a19c302ceefaecd

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