Malicious PDF — malware analysis report

Static analysis result for SHA-256 591b72b3ea6ce741…

MALICIOUS

PDF

74.2 KB Created: 2021-09-02 15:54:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 3f1f6b56534f5e1ab2cdfc66c1ffd509 SHA-1: 266724aac3274e89ab55339255536b38f725a796 SHA-256: 591b72b3ea6ce74178f4cc46c9d41dd1a099a3adf4f12b0ee1ae0b203286deaa
96 Risk Score

Malware Insights

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

The PDF contains a large number of embedded URLs, many of which point to domains that appear to be compromised or disposable, suggesting a link farm or SEO poisoning tactic. The ML classifier strongly indicated maliciousness, and the presence of multiple PDF link farm heuristics supports this. While no scripts were extracted, the structure and URL distribution are indicative of a malicious document designed to redirect users.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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://kopari.hu/files/file/vokoko.pdf In PDF document text
    • http://magiccat.pro/ckfinder/userfiles/files/beposeka.pdfIn PDF document text
    • https://bczenekar.hu/files/file/wosexatoj.pdfIn PDF document text
    • http://sinara.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/16094255758b11---pijano.pdfIn PDF document text
    • https://micast.de/wp-content/plugins/super-forms/uploads/php/files/lgf2p112artmnv8tie46glnuhj/lizibozolod.pdfIn PDF document text
    • https://okna-stv.ru/userfiles/files/jilabukajor.pdfIn PDF document text
    • https://agrotehholding.ru/wp-content/plugins/super-forms/uploads/php/files/b96f2ae8b23810c2962bfd3e216be6d0/60089421506.pdfIn PDF document text
    • http://ashioke.com/images/library/File/76045904807.pdfIn PDF document text
    • https://dienlanhhonganh.com/images/pic/file/salakugumola.pdfIn PDF document text
    • http://bannermaul.com/userData/board/file/12745292475.pdfIn PDF document text
    • https://beaumont-residence.com/wp-content/plugins/super-forms/uploads/php/files/98akitncifqtr5eqa60ls1d9og/44793917692.pdfIn PDF document text
    • http://emilygrilltogo.com/uploads/files/kovode.pdfIn PDF document text
    • https://theshairpodcast.com/wp-content/plugins/super-forms/uploads/php/files/c07781910b23458afd74d4f67fb6d5c4/48499200957.pdfIn PDF document text
    • https://destockbaby.com/ckfinder/userfiles/files/kobitipoladefifisiwakoxu.pdfIn PDF document text
    • https://holyfamilyhospitals.com/ckfinder/userfiles/files/79607615874.pdfIn PDF document text
    • https://veglifekc.org/wp-content/plugins/super-forms/uploads/php/files//tazutiporejirurete.pdfIn PDF document text
    • http://china-zub.ru/userfiles/file/20239483288.pdfIn PDF document text
    • https://www.auditek.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160ba8a6de7e39---ridaxelosadoxegabu.pdfIn PDF document text
    • http://mjsolankifoundation.com/fck/imagesfile/50582809492.pdfIn PDF document text
    • http://rayer.cn/d/files/84998293519.pdfIn PDF document text
    • http://mextro.de/upload/files/fuwulubag.pdfIn PDF document text
    • https://www.hit-education.com/wp-content/plugins/super-forms/uploads/php/files/kncuh4fr647qq88s5db5g5j0eq/88555873616.pdfIn PDF document text
    • https://cornerstonelaw.eu/userfiles//file/bifag.pdfIn PDF document text
    • https://www.eziblank.com/wp-content/plugins/super-forms/uploads/php/files/9f162834c0b4d95b7a46d87f16ec5ccb/gojirumezevebegafelu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/PmAiG5ZyT-k/uplcv?utm_term=organismos+transgenicos+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_off0000bf13.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBF13 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d72a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD72A 10940 bytes
SHA-256: 608d2b3a44e858ad96c6cbe2ce4daca1062ac9fef9a34d61b6da2d8f9bbb0e88
font_02_sfnt_off0000f053.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF053 16736 bytes
SHA-256: 115efd0f4db42eb378be4957e973d68726a7db506bb42b19c4ba320358bfec91