Malicious PDF — malware analysis report

Static analysis result for SHA-256 835c21e26b982382…

MALICIOUS

PDF

80.6 KB Created: 2021-09-07 20:21:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: aed79dfef905ff6e4ca50aef93f047b3 SHA-1: 782ef1dabfcfe9ec9c1333d17df7673527b51025 SHA-256: 835c21e26b98238262c8354caf20d429ef6bc32a628b47954c0ee435e2816fd8
96 Risk Score

Malware Insights

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

The PDF file contains a large number of embedded URLs pointing to various websites, many of which appear to be hosted on compromised or disposable domains. The ML classifier strongly indicated maliciousness, and the heuristic firings suggest this PDF is part of a link farm designed to manipulate search engine results or redirect users to malicious content. No scripts were extracted, and the document body was unreadable, but the URL structure and heuristic findings are sufficient to assess the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

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://chcial.ru/uplcv?utm_term=copy+excel+worksheet+to+new+workbook+vba PDF link annotation
    • http://dichvugiayphep.biz/upload/ck/files/zixari.pdfIn PDF document text
    • http://pericosrentcar.com.mx/wp-content/plugins/formcraft/file-upload/server/content/files/1608920194538c---lidawoxozi.pdfIn PDF document text
    • https://mosallaesf.ir/uploads/ck/files/wudobilotegavuvoki.pdfIn PDF document text
    • http://bertrandetgastineaudesigners.fr/userfiles/file/webavovogedogavobimopamad.pdfIn PDF document text
    • http://pvsystreports.com/wp-content/plugins/super-forms/uploads/php/files/uu2b359ergqb2tp5sfmo59r9e6/41570706105.pdfIn PDF document text
    • https://www.c2commercial.com/wp-content/plugins/super-forms/uploads/php/files/45b515a845d8f8f594c45120a27883cd/rotejaretegatopabene.pdfIn PDF document text
    • https://banktapeunadana.com/tapeunadana/bank2/admin/userfiles/file/99163925920.pdfIn PDF document text
    • http://hoadondientu-ptp.vn/images/ckeditor/files/sakaruzuwimavud.pdfIn PDF document text
    • http://1970fchs50thclassreunion.com/clients/1/19/19770213778af891f1b13fa25f964f50/File/3226677490.pdfIn PDF document text
    • http://www.lightingandhvacexpo.com/wp-content/plugins/super-forms/uploads/php/files/9c69391a64b60b098b4f978cc89ab9be/mobimagukotepuwowabarew.pdfIn PDF document text
    • http://www.adanakursmerkezi.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a0431a3f9a6---18904033339.pdfIn PDF document text
    • http://somersetcountybar.org/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/48504616818.pdfIn PDF document text
    • https://shoppingplanet.ro/ckfinder/userfiles/files/88280729667.pdfIn PDF document text
    • http://namlinhchivietnam.net/userfiles/image/file/lawinelegenirupedumu.pdfIn PDF document text
    • http://mastrodibaglio.it/userfiles/files/17752196015.pdfIn PDF document text
    • http://cgmorenanews.com.br/ckfinder/userfiles/files/zekazi.pdfIn PDF document text
    • http://kaupa.cz/userfiles/file/jokigojupi.pdfIn PDF document text
    • https://takipcisec.com/calisma2/files/uploads/30646344418.pdfIn PDF document text
    • https://www.financedeclined.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1609af4fc4ee87---46968172022.pdfIn PDF document text
    • https://almoheetmanpower.com/public_html/userfiles/file/lavixososoboseb.pdfIn PDF document text
    • https://erinmillssmilesdentistry.com/wp-content/plugins/super-forms/uploads/php/files/kp9t8nnri0lld2u495tlhco2d3/romojefubuf.pdfIn PDF document text
    • https://bhsbeacon.com/FCKeditor/file/25377390865.pdfIn PDF document text
    • https://xn--22ck6bdp5cach0mc23a.com/ckfinder/userfiles/files/bepuxegifik.pdfIn PDF document text
    • https://perfecthospitals.org/FCKeditor/file/waromok.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_off0000d3f3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD3F3 11012 bytes
SHA-256: f18b9fea7307034dfaf400803982c34cb60cbf711c718232c38adb7a3c0d6615
font_01_sfnt_off0000ed6b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED6B 18312 bytes
SHA-256: 5ae51041a45fad8436ee427aad3df9001bb8cda693d66203138ca06426f7b4a0
font_02_sfnt_off00011cba.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11CBA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1