Malicious PDF — malware analysis report

Static analysis result for SHA-256 bf3f4063bd1eca66…

MALICIOUS

PDF

96.9 KB Created: 2021-07-03 00:31:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: fc625f07cc0559915758ed21571236f2 SHA-1: e256fa8852cb669d3daca936b036de417410d2d7 SHA-256: bf3f4063bd1eca669e39cf7f74f0b28ecdf8443b2a500dc306863f6c2a71ecf6
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links pointing to compromised WordPress sites, which in turn host other PDF files. This structure suggests a link farm designed to distribute malicious content, likely for phishing or malware delivery. The ClamAV detection and ML classifier strongly indicate malicious intent, with the URLs serving as the primary indicators of compromise.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9936

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://krisoc.ru/uplcv?utm_term=algorithm+analysis+questions+and+answers
    • https://noks.cz/wp-content/plugins/formcraft/file-upload/server/content/files/1608b0564e9f09---2157342656.pdf
    • https://yastudio.net/wp-content/plugins/super-forms/uploads/php/files/9d83451ae8d8331f95bf3fed3ff8fa7d/pulorebamenulama.pdf
    • https://www.axelendinggroup.com/wp-content/plugins/super-forms/uploads/php/files/679fabb59087e92b4231ddea6efc3d09/mawep.pdf
    • http://beergolfers.com/blog/images/file/66196684930.pdf
    • http://moriefrusca.com/userfiles/files/wuzosorozulumamokek.pdf
    • http://ptaki.info/imgekoprojekty/files/42243537613.pdf
    • https://3dreamvr.com/wp-content/plugins/super-forms/uploads/php/files/30de886980d8d0fc3ab09936f38a65a9/91646494377.pdf
    • http://www.peopleoftheheath.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b523053af21---41506146900.pdf
    • http://bouncebodysupplements.com/newerac2c/userfiles/file/5265917627.pdf
    • https://mediabandit.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b128169004e---fegizawajifavigujagu.pdf
    • http://www.sunaryem.com.tr/wp-content/plugins/super-forms/uploads/php/files/tapt5np6jpl0kil8clg29nmer6/jokofew.pdf
    • http://skup-laptopow.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609e6cab31390---24034524519.pdf
    • https://www.cukoyem.com.tr/wp-content/plugins/super-forms/uploads/php/files/jljjp0guth6mmd6r05oad3ti50/putopemozebez.pdf
    • http://uniondeautoescuelas.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c9b9bedd813---74876601394.pdf
    • https://phase1acoustics.com/wp-content/plugins/formcraft/file-upload/server/content/files/16071042682812---28787166476.pdf
    • http://computer-rudolstadt.de/upload/file/xivisakemewelojokeri.pdf
    • https://gpagroup.in/wp-content/plugins/formcraft/file-upload/server/content/files/1608e921965c13---35770931199.pdf
    • http://sieuthivatlieuhoanthien.com/upload/files/26493253568.pdf
    • http://hillsdale66ersreunion.com/clients/c/c6/c679c52642bc64dd8629b98fb95ccc77/File/luneresamovejobadavidilis.pdf
    • http://studiolegalezullo.eu/userfiles/files/31340110400.pdf
    • http://robertfeinberglaw.com/images/edit_images/file/degaxukolu.pdf
    • https://iaetindia.com/ckfinder/userfiles/files/pajagatimujes.pdf
    • https://maloneslandscape.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d74bde1af0c---navebujo.pdf
    • https://bdaudit.ro/userfiles/file/pewaruranowapuxu.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000111f5.bin
95ed8d6c7c809f9641c0d1ab829a9f9d35ae6c16873ed0875f78bd8da4daed0e
pdf-font-stream PDF embedded font (sfnt) at offset 0x111F5 11124 bytes
font_01_sfnt_off00012b4f.bin
46f97ce59a5c24a899f6c7c1a766d60d309cc2c7db4fd9c2dd868c0a29c2cf30
pdf-font-stream PDF embedded font (sfnt) at offset 0x12B4F 18516 bytes
font_02_sfnt_off00015c1c.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x15C1C 16792 bytes