Malicious PDF — malware analysis report

Static analysis result for SHA-256 404bfba29c27c86e…

MALICIOUS

PDF

104.8 KB Created: 2021-09-05 12:47:34 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 5fb3bc20b2d32de45f5864b1031c3830 SHA-1: 790846bab02ee8d6ce3bcea1ea4a03ee9553f3cb SHA-256: 404bfba29c27c86e33568c3843322f1b1e0f2984fa374256811cc38fd8be59ef
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains a large number of external URIs and link farms, with several pointing to compromised CMS upload directories. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or SEO abuse. No scripts were extracted, and the document body was unreadable, but the heuristic firings are sufficient to assess the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9877

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 http://wecans.net/_UploadFile/Images/file/58387859448.pdf In PDF document text
    • https://carthink.org/wp-content/plugins/formcraft/file-upload/server/content/files/1606f32f53b447---zimilasevawo.pdfIn PDF document text
    • http://slenderclub.cz/ckfinder/userfiles/files/29198101108.pdfIn PDF document text
    • http://technoculture.cz/admin/upload/file/pimewinivurabesuwive.pdfIn PDF document text
    • https://inoxquochoang.com/app/webroot/files/images/pages/files/39809716409.pdfIn PDF document text
    • http://espacioschillout.es/images/admin/file/63303808208.pdfIn PDF document text
    • http://szakkepzosiklos.hu/upload/file/mubaxef.pdfIn PDF document text
    • https://www.harnoordesigns.com/wp-content/plugins/super-forms/uploads/php/files/m6lv2rr1q3cpiap8cs2b3e4u74/xesalobezatojetomosi.pdfIn PDF document text
    • http://skolicka.eu/foto/images/file/32034334349.pdfIn PDF document text
    • http://skkl.cn/filespath/files/20210904025606.pdfIn PDF document text
    • http://debeleven.net/UserFiles/File/gazegugujilekegelupe.pdfIn PDF document text
    • http://bischofs-scheune.de/userfiles/file/pigogu.pdfIn PDF document text
    • http://studiosantomauro.it/userfiles/files/pibejuxijosusizuwes.pdfIn PDF document text
    • https://centrosteadycam.it/wp-content/plugins/super-forms/uploads/php/files/1f3bc7f8d930e811e6fe4d2300e2f089/dagotenaguvozagasunota.pdfIn PDF document text
    • https://vanchuyenduongsat.vn/upload/files/pozupukixike.pdfIn PDF document text
    • https://ebooksweb.net/files/file/41195966585.pdfIn PDF document text
    • http://skuplaptop.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160cbbcfc12230---25232349978.pdfIn PDF document text
    • https://santevita-bg.com/ckfinder/userfiles/files/bidofesimun.pdfIn PDF document text
    • https://at-studio.tw/app/webroot/userfiles/files/20210630_193622.pdfIn PDF document text
    • http://oneself.pro/wp-content/plugins/formcraft/file-upload/server/content/files/160789cf47c794---loranebupik.pdfIn PDF document text
    • https://callhfelectric.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606fffbb8a101---nezeladu.pdfIn PDF document text
    • http://toanlinh.vn/upload/files/99596940335.pdfIn PDF document text
    • https://amenagementsoleil.com/wp-content/plugins/formcraft/file-upload/server/content/files/16071deaac2d38---6947190592.pdfIn PDF document text
    • https://aldea.work/wp-content/plugins/super-forms/uploads/php/files/ca0f7adb1c901909784c5d1d028283e4/56438184349.pdfIn PDF document text
    • http://aj-freight.com/ckfinder/userfiles/files/96291847152.pdfIn PDF document text
    • http://www.sg-callenberg.de/wp-content/plugins/formcraft/file-upload/server/content/files/160756901e0863---benumirenos.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1xuhb7AK25c/uplcv?utm_term=celpip+listening+practice+test+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_off00013001.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13001 10708 bytes
SHA-256: 631f1fc9f0d5e5b0a376b1cf06aed30e67ca5c40ebbc667eebe7e4a7bb0cdf1c
font_01_sfnt_off00014882.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14882 19936 bytes
SHA-256: 0795bc04dc704f3c45d663a86a1175e3ad59da4df5d898d4bd0ffa7810a6bb75
font_02_sfnt_off00017d31.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x17D31 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1