Malicious PDF — malware analysis report

Static analysis result for SHA-256 823fa82cc0054403…

MALICIOUS

PDF

67.9 KB Created: 2021-09-27 01:53:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: f6eee1410b1744ee875f3dfefe48a4d5 SHA-1: bea83338b36877a988700fae4f911b3bed6b44c1 SHA-256: 823fa82cc005440389faeaa8ac460dc3eaa313412f3ec9e20f5ea92fd339621b
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous external links, many pointing to compromised WordPress sites or disposable hosting, indicating a link farm or redirection scheme. The ML classifier strongly flagged this PDF as malicious. The presence of multiple external URIs and link farm heuristics suggests an attempt to direct users to potentially malicious content or for SEO manipulation.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9966

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://laborke.ru/uplcv?utm_term=ia+chemistry+examples PDF link annotation
    • http://theofficefurniturestore.com/ckfinder/userfiles/files/21627694358.pdfIn PDF document text
    • http://highendschmiede.de/highendfiles/file/54933086567.pdfIn PDF document text
    • http://nguyenthaotech.com/upload/files/lezigi.pdfIn PDF document text
    • http://becro-plast.hr/wp-content/plugins/formcraft/file-upload/server/content/files/16131818a913d5---togotebafigitofonesisivo.pdfIn PDF document text
    • https://fabriziochessa.it/userfiles/file/naxarajefijufanudepopax.pdfIn PDF document text
    • http://purplebyanki-com.bvirani.com/ckfinder/userfiles/files/kidamuzokufugirode.pdfIn PDF document text
    • http://cokhihoangvinh.com/uploads/userfiles/file/68004539697.pdfIn PDF document text
    • http://lavera.it/wp-content/plugins/formcraft/file-upload/server/content/files/16149e04cb8730---38528811058.pdfIn PDF document text
    • https://www.ediliziaindustriale.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614752e7ac556---gexowimomumimiwubosowof.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/16150b53ae09e9---29637321160.pdfIn PDF document text
    • http://picart-personal.pl/fckupload/upload/file/42072927623.pdfIn PDF document text
    • http://gioithieu.btccorp.vn/uploads/files/daxavotidalawe.pdfIn PDF document text
    • http://hyundaiokla.com/uploads/files/midepulofegemutafal.pdfIn PDF document text
    • https://realimpacto.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16149783a3c320---wirugu.pdfIn PDF document text
    • http://www.kreasoft.mx/wp-content/plugins/formcraft/file-upload/server/content/files/1614853f9d2a2c---10782565216.pdfIn PDF document text
    • https://cpsguffanti.com/uploads/file/jizedipuxun.pdfIn PDF document text
    • http://dtyxbpzx.com/filespath/files/20210902154418.pdfIn PDF document text
    • https://www.lucaslobker.com/minor/ckfinder/userfiles/files/gudopu.pdfIn PDF document text
    • http://www.siscard.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613d178e6fbdc---25673912679.pdfIn PDF document text
    • http://kursadowicz.pl/Upload/file/vojatuxasotutamutigux.pdfIn PDF document text
    • http://zadonskiy.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1614b41e6dd6a2---62545028710.pdfIn PDF document text
    • http://ayrh.internet-match.com/upload/files/24113860926.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_off0000af20.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAF20 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000c737.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC737 10584 bytes
SHA-256: 60b2106a4c3d63aa39572e29095836765c476bc6a37a4d703ee4223d00d61b3b
font_02_sfnt_off0000df69.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF69 14256 bytes
SHA-256: e43e5b1fc8c6e5a870205693d1dcc2ab647063b7c826bfe7c4357415dba6272a