Malicious PDF — malware analysis report

Static analysis result for SHA-256 f3f6dca21ffe7c8a…

MALICIOUS

PDF

78.7 KB Created: 2021-09-08 02:43:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: f542f9e9c132185e34d8565c96f4e5fc SHA-1: e96c11ab8c0c99696452e2a20666ac4350b2928f SHA-256: f3f6dca21ffe7c8adeee57a032e434386048d310dc9b262d49f590fcc9924302
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous embedded URLs that point to compromised WordPress sites, suggesting a link farm or SEO poisoning attack. The ML classifier strongly indicated maliciousness, and the presence of multiple external URIs and link farms supports this. No scripts were extracted, and the document body was unreadable, limiting further analysis of specific payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 5

  • 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://infrive.ru/uplcv?utm_term=panghalip+na+pananong+worksheets+sa+grade+3 PDF link annotation
    • https://higher-reason.com/wp-content/plugins/super-forms/uploads/php/files/ca9ej1p13n928b3breo2klja16/34689404096.pdfIn PDF document text
    • http://fabrykakonwersji.pl/wp-content/plugins/super-forms/uploads/php/files/9351eeeaa47bb6d498a735dcf7806b12/36929504464.pdfIn PDF document text
    • http://bsa-billiard.by/images_from_html_editor/file/manemimepatafobajeb.pdfIn PDF document text
    • https://sdyh.gr/wp-content/plugins/super-forms/uploads/php/files/dh3m0luaihg9qdhul8b76o6sd5/75928930294.pdfIn PDF document text
    • https://www.a2zmedical.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1609bde24da5c9---bisijoninulojataj.pdfIn PDF document text
    • https://www.le-domaine-de-hauterive.fr/ckfinder/userfiles/files/gudebazoriwikotuzijer.pdfIn PDF document text
    • http://www.dj-csnl.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160c4053fb110f---87083250474.pdfIn PDF document text
    • https://cullinanconstruction.com/wp-content/plugins/super-forms/uploads/php/files/4jiumi7f2984648kolqrv725r2/sozumozukidejuluje.pdfIn PDF document text
    • http://www.infranetltd.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a4af6b8a9d2---65573872741.pdfIn PDF document text
    • http://diamondsnspurs.com/clients/12200/File/nerere.pdfIn PDF document text
    • https://www.jahnigterbraak.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160adaa9102be6---12459095848.pdfIn PDF document text
    • http://www.majoriscambio.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1609ce570984ea---13733872782.pdfIn PDF document text
    • http://com123.vn/uploads/file/51526711874.pdfIn PDF document text
    • http://ar-intl.net/wp-content/plugins/super-forms/uploads/php/files/qnn4t8h5i2tt591fikimrm3hu7/ninimodo.pdfIn PDF document text
    • http://kleiberit.ru/files/file/89890699705.pdfIn PDF document text
    • http://cuiquji.net/d/files/11192702775.pdfIn PDF document text
    • http://www.reenactmentmarket.eu/images/wyswig_images/file/44687096649.pdfIn PDF document text
    • https://mannerfeltdesignteam.se/ckfinder/userfiles/files/30548460826.pdfIn PDF document text
    • https://elpmarketing.ca/wp-content/plugins/super-forms/uploads/php/files/b3899d49b4439b890f8acc4cd48e7977/13944613052.pdfIn PDF document text
    • https://reflexlighting.com/wp-content/plugins/super-forms/uploads/php/files/21b1762464603a751bb011c1862dce18/vurotiwelixewi.pdfIn PDF document text
    • http://ebslang.net/_UploadFile/Images/file/fitewevuvexunimojelemanin.pdfIn PDF document text
    • 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_off0000cdc2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCDC2 11020 bytes
SHA-256: a275b8c4d5a17a51654ae4bfc8dd46e0bc0e3d43f07c134e65bd5d4001f8c8c8
font_01_sfnt_off0000e739.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE739 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000ff4b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF4B 18060 bytes
SHA-256: a31a9578d3705222e7b5e08d5d3428949f168cc841c763e63f404ac87057e2f2