Malicious PDF — malware analysis report

Static analysis result for SHA-256 3f21d610b013bb98…

MALICIOUS

PDF

83.2 KB Created: 2021-09-05 21:55:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 698133c4ae3d7dae55a1407efab5cedc SHA-1: 28f81f54c3cbae1cb26509c2500c2d112f340596 SHA-256: 3f21d610b013bb98e914506de198ace1a2c077c5725250b32d26c997cfbaebba
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains a large number of embedded URLs, many of which point to compromised WordPress sites. The ML classifier strongly indicates maliciousness. The primary function appears to be acting as a link farm, likely to manipulate search engine rankings or to serve as a distribution point for further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

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://divorcioconsensual.com.br/wp-content/plugins/super-forms/uploads/php/files/f9687895c7586ba70a82d0c032b81b93/46313583726.pdf In PDF document text
    • http://vet-arrighicolangelicristilli.eu/userfiles/files/98102864243.pdfIn PDF document text
    • http://miskolciharsona.hu/pictures/file/majalajik.pdfIn PDF document text
    • https://associazionedynamica.it/uploads/file/45362102709.pdfIn PDF document text
    • https://lorenzonimmigrationlaw.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bcff74ae724---tunafenenaxasebo.pdfIn PDF document text
    • https://wscnaturalhealings.com/wp-content/plugins/super-forms/uploads/php/files/e7831d07c3ca034bc08b13fe9b7f0e75/livexurizalezijunupe.pdfIn PDF document text
    • https://action-roofing.com/wp-content/plugins/super-forms/uploads/php/files/60ecf1a7e69fad58dbd380b25db7e4c8/29642484362.pdfIn PDF document text
    • https://www.modianodesign.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a3652bda76a---73750834323.pdfIn PDF document text
    • https://dwitunggaljaya.com/sitefiles/file/23038069944.pdfIn PDF document text
    • https://www.swx.global/wp-content/plugins/super-forms/uploads/php/files/0fe7e88a54db210c935cc90a207d4d3e/dibeja.pdfIn PDF document text
    • https://al-farh-iq.com/upload/userfiles/file/59799961564.pdfIn PDF document text
    • http://danies.ru/ckfinder/userfiles/files/54591063749.pdfIn PDF document text
    • http://mywayrtk.info/userfiles/file/timarubazijowaragufari.pdfIn PDF document text
    • https://bodegoncriollo.com/userfiles/file/lopipi.pdfIn PDF document text
    • http://basyapiemlak.com/yukleme_klasoru/userfiles/file/jipiwox.pdfIn PDF document text
    • http://automotiveenergy.cz/userfiles/file/60972809848.pdfIn PDF document text
    • https://www.3dreamchurch.com/wp-content/plugins/super-forms/uploads/php/files/0c39477695c40f3157f2cbd977d8b607/sanawuzu.pdfIn PDF document text
    • http://www.danvillern.com/wp-content/plugins/super-forms/uploads/php/files/8892lhisqccvpvqv5fik6n3p45/50869893320.pdfIn PDF document text
    • https://smoothnomad.com/wp-content/plugins/super-forms/uploads/php/files/ammn0anuadqciph254hum4mdf0/pirafemakukanopatabikan.pdfIn PDF document text
    • https://www.kiteschule-kiel.de/wp-content/plugins/formcraft/file-upload/server/content/files/160f982cb19c51---57049500424.pdfIn PDF document text
    • http://theleadershipworks.com/PO2/UPFILE/userfiles/files/6245305185.pdfIn PDF document text
    • https://pasarant0g3l-turbo-h1t.com/contents/files/76451194266.pdfIn PDF document text
    • http://daiichigroup.net/uploads/news_file/22142880597.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/DOqCt-cVA4I/uplcv?utm_term=personal+protective+equipment+nursing+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_off0000def3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDEF3 18084 bytes
SHA-256: 7defda819aa4166f8ddd1cad3db58d54ed7127c3a1bffa3f08ac72ceacb8ab4b
font_01_sfnt_off00010cef.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10CEF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012506.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12506 11276 bytes
SHA-256: a600cc206d2df893e57a3f716884022471de198670f5508c68a2d54212bcca4e