Malicious PDF — malware analysis report

Static analysis result for SHA-256 d43085ceb5f4ba66…

MALICIOUS

PDF

73.9 KB Created: 2021-09-19 20:43:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 23ef069b6546751b1a703910e283d996 SHA-1: 9ce13eee7f4e6c3376de273274a0857f7413dd98 SHA-256: d43085ceb5f4ba66fe81a1088ed5cf35decfb149efc3d59374cdf3a764abd41d
136 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous links, many pointing to compromised WordPress sites or disposable hosting, suggesting a link farm designed to redirect users to malicious content. The ML classifier strongly indicates maliciousness, and the presence of algorithmically generated URLs further supports this. The sample's primary function appears to be distributing further malicious payloads via these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9947

Heuristics 6

  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://coretry.ru/uplcv?utm_term=allwinner+t8+mcu+update PDF link annotation
    • http://dywin.com/uploadfile/files/kefumeviribolajarinetub.pdfIn PDF document text
    • https://lexconsulting.ro/webroot/files/media/53513451594.pdfIn PDF document text
    • http://acupunctuuryao.nl/ckfinder/userfiles/files/xorifekemogu.pdfIn PDF document text
    • http://slbreakingnews.com/ckfinder/userfiles/files/4708633453.pdfIn PDF document text
    • http://dh-cell.net/ckfinder/userfiles/files/zabumariviparogutiw.pdfIn PDF document text
    • http://taaltoetsvo.nl/userfiles/file/17850788148.pdfIn PDF document text
    • https://www.landalastadservice.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613ecbefe0893---pojejominukis.pdfIn PDF document text
    • http://www.cafeinca.com/img/public/contenido/file/60332660362.pdfIn PDF document text
    • http://norilskgu.ru/userfiles/file/78947885385.pdfIn PDF document text
    • http://peaceinsrilanka.lk/ckfinder/userfiles/files/mafotuzuxoniwufivobiwipep.pdfIn PDF document text
    • http://isagenixmakessense.com/ckfinder/userfiles/files/37958059150.pdfIn PDF document text
    • http://archiwum.wyryki.eu/admin/ckfinder/userfiles/files/bofonadibuseguseribo.pdfIn PDF document text
    • https://www.totspotdaynursery.co.uk/ckfinder/userfiles/files/metukuzagasejiwavujijotik.pdfIn PDF document text
    • https://pointswestliving.com/ckfinder/userfiles/files/73314673703.pdfIn PDF document text
    • https://www.horisunmauritius.com/wp-content/plugins/super-forms/uploads/php/files/fb8f78406ff3350857d1563346d95f56/wumotolujejudo.pdfIn PDF document text
    • https://www.mybizwebsites.com/wp-content/plugins/formcraft/file-upload/server/content/files/161358fed269f1---74893887689.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613825c6ea500---soxadolusexokarof.pdfIn PDF document text
    • http://chapaconoticias.com/assets/ckfinder/core/connector/php/uploads/files/nasunamasamimuxezakepavu.pdfIn PDF document text
    • https://ginniglobal.com/uploads/file/bedadanotemonimitaviba.pdfIn PDF document text
    • http://auburn-companies.com/userfiles/files/13688688415.pdfIn PDF document text
    • https://nayyaralidada.net/alpha/ckfinder/userfiles/files/37410679872.pdfIn PDF document text
    • https://cfaegaianascente.pt/portal/userfiles/files/sabudafofopikigiduwed.pdfIn PDF document text
    • https://www.hintonassociates.com/wp-content/plugins/super-forms/uploads/php/files/927ac9577021d345aef1680e261ed56c/98278140708.pdfIn PDF document text
    • https://linker.tw/files/tazurinidaxotelovefopake.pdfIn PDF document text
    • http://carraracucinecomponibilitrapani.it/userfiles/files/todak.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_off0000b740.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB740 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cf57.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCF57 10760 bytes
SHA-256: e58d5f8d25f63bab35caff24bb5237401e7762f43d7c648063e16e8f4d153a49
font_02_sfnt_off0000e825.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE825 19500 bytes
SHA-256: cfbb1af945f42b2bf200600075475806ea26e5fb3ab4b2802cdfe7f57dc5bdee

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