Malicious PDF — malware analysis report

Static analysis result for SHA-256 f155b7ac4a6e188a…

MALICIOUS

PDF

77.1 KB Created: 2021-09-04 21:02:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: c54a3fc99fc5c23ea960bef82ce3ef9f SHA-1: 8014385599d45ef550714bee6e403dd76bede020 SHA-256: f155b7ac4a6e188a4b10243b936e214a817916540b051511d44c27eb4378ea50
96 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to other PDF files hosted on various websites. Several heuristics indicate that these links are part of a link farm, potentially hosted on compromised CMS platforms. The ML classifier strongly flagged this PDF as malicious, suggesting its primary purpose is to redirect users to external, potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

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://cructi.ru/uplcv?utm_term=curriculum+educativo+definicion+pdf PDF link annotation
    • http://woodlander.sk/grafika/file/43569063154.pdfIn PDF document text
    • https://snabavto.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d6a210a049a---76103257055.pdfIn PDF document text
    • http://www.stemcellhairclinic.com/files/files/29520876426.pdfIn PDF document text
    • http://piri-piri.pl/ckfinder/userfiles/files/42439219157.pdfIn PDF document text
    • http://magogaralbamoble.com/galeria/files/54313280073.pdfIn PDF document text
    • http://unitekinfostructures.com/userfiles/file/nosarusabireju.pdfIn PDF document text
    • https://utilitydiscount.com/wp-content/plugins/formcraft/file-upload/server/content/files/16086b7a0f07d3---93165957766.pdfIn PDF document text
    • https://c4ir.ae/wp-content/plugins/super-forms/uploads/php/files/d54s9rpvd7bnmc23ae3avsamv4/fisem.pdfIn PDF document text
    • https://angkalaris.com/contents/files/74561386446.pdfIn PDF document text
    • https://whereestar.com/marinarubicon/admin/file/8503128123.pdfIn PDF document text
    • http://irmascaritasdejesus.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/16113e6c51e065---40109735961.pdfIn PDF document text
    • http://naplesredeals.com/userfiles/files/49577660271.pdfIn PDF document text
    • http://shopcloud.cloud//ckfinder/userfiles/files/26398058396.pdfIn PDF document text
    • http://saludocupacionalpso.com/home/wp-content/plugins/formcraft/file-upload/server/content/files/160978fda30234---26372059188.pdfIn PDF document text
    • https://spencershaulageltd.co.uk/wp-content/plugins/super-forms/uploads/php/files/804a99d32395bdeed7e82517d42eb2a6/fubof.pdfIn PDF document text
    • http://bajcsidavidfoto.com/_user/file/25659159378.pdfIn PDF document text
    • https://getlovebooks.com/wp-content/plugins/super-forms/uploads/php/files/7effc7b8b18000e1085c167a799e11ae/43128346619.pdfIn PDF document text
    • http://suapaiatuipelehakefamily.com/clients/80707/File/susolabopupi.pdfIn PDF document text
    • http://playfromhome.org/clients/4/49/49939bf6a151252ba1adfe53d1befa29/File/43866063987.pdfIn PDF document text
    • http://kimandyoo.com/userfiles/file/pomorelaxobimor.pdfIn PDF document text
    • http://russkiivopros.com/images/FCKeditor/file/4190330860.pdfIn PDF document text
    • https://alcc.vn/wp-content/plugins/super-forms/uploads/php/files/18p3m4pnvsqf9kdrdoi00s2b54/mozufujebasexefibunebe.pdfIn PDF document text
    • http://dentherapia.hu/files/file/34952737645.pdfIn PDF document text
    • http://wypelnienia.kratex.pl/wp-content/plugins/super-forms/uploads/php/files/277374726d2a74f7edde247cebcf931b/faloxevavubuvimirefazexo.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_off0000c662.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC662 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000de79.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE79 10812 bytes
SHA-256: 4123ac1a9f3ffcd22709940de7ddf652e2ec06d0d16fc8bf101ed91eb3f76f13
font_02_sfnt_off0000f767.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF767 18288 bytes
SHA-256: 5a395c0d9fe5efbdfe87ed93c4e3145e0a1572d75ad5ce7998547512f921f83c