Malicious PDF — malware analysis report

Static analysis result for SHA-256 b94919b9be5388c2…

MALICIOUS

PDF

71.5 KB Created: 2021-06-10 12:52:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-26
MD5: c9c367d2b61930fb185f469ddb904ba4 SHA-1: ef4239be732d46d89bc879842a378a1ecf431de9 SHA-256: b94919b9be5388c26caf655a0458750efbae2932121fe6cc69b9eeb28c18cbb5
96 Risk Score

Malware Insights

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

The PDF document contains a large number of external URIs, many of which point to compromised CMS upload directories or disposable hosting. This structure suggests the document is designed as a link farm to redirect users to potentially malicious websites. The ML classifier strongly supports the malicious nature of this PDF.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://wastran.ru/uplcv?utm_term=pdf2word+free+online PDF link annotation
    • https://directprocessors.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a57822109be---84057637226.pdfIn PDF document text
    • http://esoftland.com/userfiles/file/binoziruxer.pdfIn PDF document text
    • https://discoverapartmentsforrent.com/wp-content/plugins/super-forms/uploads/php/files/60566d50666c8df8256e073f7e4a1665/66977907011.pdfIn PDF document text
    • https://www.ferienhof-schneider.de/wp-content/plugins/formcraft/file-upload/server/content/files/1609b5d8eb8875---91646723323.pdfIn PDF document text
    • http://kadernictvo-svetlana.sk/editor_uploads/system/files/5079988934.pdfIn PDF document text
    • http://sklepjola.pl/userfiles/file/fejun.pdfIn PDF document text
    • http://optikametuje.cz/userfiles/file/69853462912.pdfIn PDF document text
    • http://traditionsradio.com/wp-content/plugins/super-forms/uploads/php/files/1vobmnbjt367fuefk7s5o0pqh0/raradiperurowig.pdfIn PDF document text
    • https://baodinhsolar.com/wp-content/plugins/super-forms/uploads/php/files/acn6udagirpq00nekmti3pq1jo/lunabagomuk.pdfIn PDF document text
    • https://advancedbusiness.co/wp-content/plugins/super-forms/uploads/php/files/08db98c0ecc95f3c3add097dec44f0ed/rutugulugipotajigiwot.pdfIn PDF document text
    • http://thankschicken.com/uploads/files/xanimopofetu.pdfIn PDF document text
    • http://greenplanetnepal.com/userfiles/file/jivofivurerolisux.pdfIn PDF document text
    • https://assurancemauricie.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609dd39c0a5c3---35632965426.pdfIn PDF document text
    • http://milcontabil.com.br/wp-content/plugins/super-forms/uploads/php/files/km57b2br479sjid1raqvgmjd44/gusevezipizuxusetu.pdfIn PDF document text
    • http://www.sparkprototypes.com/wp-content/plugins/formcraft/file-upload/server/content/files/16074b4fb1c8cd---rinogomafobojax.pdfIn PDF document text
    • http://asijskepotraviny.cz/files/file/9821817871.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000de0f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE0F 4740 bytes
SHA-256: 1c7d84d392174a6678c6dd905c1b59d84ce79185dd5ddaf0fdb16280dbfd29bd
font_01_sfnt_off0000ee54.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE54 10360 bytes
SHA-256: f9f42b572a313c9972347bad674800efab00a631114de19de8d04f922dd9ab25