Malicious PDF — malware analysis report

Static analysis result for SHA-256 81941824cf54e54a…

MALICIOUS

PDF

73.0 KB Created: 2021-09-03 13:11:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: f6ca1050ae5c5bb74e0e6c779ddf8611 SHA-1: 0d73e01e85a30e38013f99aa4b12f7d315086fc9 SHA-256: 81941824cf54e54accbaa8991000578cd47e36f1a15e5864e102619bf037ebaa
156 Risk Score

Malware Insights

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

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous URLs, many pointing to compromised CMS uploads or disposable hosting, suggesting it functions as a link farm. The primary purpose appears to be directing users to external, potentially malicious, websites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

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://supermagnum-bg.com/ckfinder/userfiles/files/55446033587.pdf In PDF document text
    • http://pointerboards.com/uploads/admin/files/jamuxekiwilene.pdfIn PDF document text
    • http://anvlaw.com/userfiles/file/33207441508.pdfIn PDF document text
    • http://allprintusa.com/admin/images/file/66879983909.pdfIn PDF document text
    • https://www.weldcor.ca/public/ckfinder/userfiles/files/duleselix.pdfIn PDF document text
    • http://aaaexpressheating.com/userfiles/file/rufugenojuxawapawipudi.pdfIn PDF document text
    • https://www.bouldersudbury.org/wp-content/plugins/formcraft/file-upload/server/content/files/1607654de6918b---36304312017.pdfIn PDF document text
    • https://www.charroninc.com/wp-content/plugins/super-forms/uploads/php/files/55341b1b44e0ccb10ddca6c816959401/kanamixemu.pdfIn PDF document text
    • http://vibrosystem.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1608a2cd26f299---75909089723.pdfIn PDF document text
    • https://davidfoleyinc.com/userfiles/file/28372611310.pdfIn PDF document text
    • https://pluckywize.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607e1efee12e1---menorafewotuvakemopa.pdfIn PDF document text
    • https://www.cukoyem.com.tr/wp-content/plugins/super-forms/uploads/php/files/1na897kga0eotvncukn4ucsts5/68338503373.pdfIn PDF document text
    • http://lavera.it/wp-content/plugins/formcraft/file-upload/server/content/files/160f3c4ebbb5c0---82349331872.pdfIn PDF document text
    • http://lev-steklo.ru/userfiles/file/vosedojezupena.pdfIn PDF document text
    • https://ambientltg.com/wp-content/plugins/super-forms/uploads/php/files/1190d98a6c01456995d9de04cff5c6b8/89406720804.pdfIn PDF document text
    • http://kennyre.com/wp-content/plugins/formcraft/file-upload/server/content/files/16098dd0864068---65032437848.pdfIn PDF document text
    • https://davebakeragency.com/wp-content/plugins/super-forms/uploads/php/files/8bf5c24058e5eef9a4da6a145d25d5bf/65845584995.pdfIn PDF document text
    • http://patroha.hu/file/lijerurup.pdfIn PDF document text
    • https://postscriptproductions.com/wp-content/plugins/formcraft/file-upload/server/content/files/160791c43c808b---fozidojorugalulu.pdfIn PDF document text
    • https://marljivo.hr/UserFiles/files/55704733804.pdfIn PDF document text
    • https://lesfeesdelhetre.fr/upload/files/xifajosivedo.pdfIn PDF document text
    • https://psfund.org/public/uploads/files/cms_files/vurufabijalibimugera.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/LPIa9PGmDLg/uplcv?utm_term=convert+multipage+tiff+to+pdf+using+itextsharpPDF 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_off0000b911.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB911 16536 bytes
SHA-256: 537ede416dd2281875489a03e5e7aa31d39373f3ed013c6a8e43e6a84dbcd843
font_01_sfnt_off0000e3f0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE3F0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000fc07.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC07 11244 bytes
SHA-256: 049c2d80d128c8cb987c4c9439ab73488d83ef841d99cb8f7acd44ea27e4c06e

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