Malicious PDF — malware analysis report

Static analysis result for SHA-256 105ca9e4a6e14fb3…

MALICIOUS

PDF

68.4 KB Created: 2021-06-25 00:52:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-11
MD5: f853518b2d1ee07e167b921fbb605fdb SHA-1: f0393b1cb571154df3216129084c890b9319d47f SHA-256: 105ca9e4a6e14fb3e1f2ea64a9554db79456d8faa0524114fa836de5afa48837
156 Risk Score

Malware Insights

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

The PDF was flagged by ClamAV as Pdf.Phishing.Trojan and a machine learning classifier indicated a high probability of maliciousness. Heuristics identified it as a link farm pointing to compromised CMS uploads and disposable hosting, suggesting an attempt to redirect users to malicious sites. The document body, though heavily obfuscated, contains metadata related to wkhtmltopdf, indicating it was likely generated programmatically.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 http://takemehometomatoes.com/ckfinder/userfiles/files/fudituloxanenemikuv.pdf In PDF document text
    • http://math-talk.kr/wp-content/plugins/super-forms/uploads/php/files/bi1e0nfbqs0uuafupct582u5k7/61849798666.pdfIn PDF document text
    • https://www.beachesbrewing.com/wp-content/plugins/super-forms/uploads/php/files/9afc559fb638ae99ceaa51eaef2ec7af/68671099652.pdfIn PDF document text
    • http://bualuang101.com/backoffice/upload/files/18976447476.pdfIn PDF document text
    • https://donnasalon.ru/wp-content/plugins/super-forms/uploads/php/files/e35566341bd5a4de168fc07913a35387/sakav.pdfIn PDF document text
    • https://proektasis.gr/admin/spaw2/uploads/files/mefiromonigokufe.pdfIn PDF document text
    • https://www.davidcosz.de/wp-content/plugins/super-forms/uploads/php/files/c42lheoetsap1d7sb2ejkdak94/wofeveligetukesirej.pdfIn PDF document text
    • http://richiefamilyreunion.com/clients/7/7d/7d03816b951c94fc7c065ced7c7ccdcd/File/sigenoxeresijosowenis.pdfIn PDF document text
    • http://www.mtpartnersfl.com/wp-content/plugins/formcraft/file-upload/server/content/files/16089062e34e42---janokijokijojobobeturew.pdfIn PDF document text
    • http://lawrence-spruill.com/clients/42275/File/xorigizatujo.pdfIn PDF document text
    • http://beijingxinzhi.com/userfiles/file/20210513235417_240341905.pdfIn PDF document text
    • https://martybermanassociates.com/wp-content/plugins/super-forms/uploads/php/files/2270f1ab8d448b9e5ce28116c55274bb/rudaxanijoxarixewuve.pdfIn PDF document text
    • https://reifenscho.de/wp-content/plugins/formcraft/file-upload/server/content/files/160bde1e50d102---99927952641.pdfIn PDF document text
    • https://www.temsilcisitesi.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d21218883ec---fanizonafuwatutuwobe.pdfIn PDF document text
    • https://rpitrade.com/ckfinder/userfiles/files/xulinaz.pdfIn PDF document text
    • http://naturallabs.de/userfiles/file/tisawesefepotimu.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/6naE_Nh8_CY/uplcv?utm_term=positive+adjectives+that+start+with+the+letter+yPDF 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000cb1b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB1B 5356 bytes
SHA-256: 62a50221d392fd6bb366f6fefa400d763acab4e8c518e12e5c84664a9230e99e
font_01_sfnt_off0000dd6a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD6A 10792 bytes
SHA-256: 53c969909844b6e43670b3d1f25473e55132a0ffd9b68366c635144ad198ea66