Malicious PDF — malware analysis report

Static analysis result for SHA-256 b1c3fc4e2f2d03fd…

MALICIOUS

PDF

70.9 KB Created: 2021-09-29 03:25:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 4d81e6edee40b6ea9bcea9132b0a7827 SHA-1: d8e45d1d781c06c4dfabc31d47f27d350443a1c2 SHA-256: b1c3fc4e2f2d03fdc79bcbf5692353397c1031e269e8f01dd9a24a315196badd
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file identified as malicious by ClamAV and an ML classifier. It contains numerous embedded URLs, many pointing to compromised CMS uploads or disposable hosting, suggesting a link farm or redirection scheme. The presence of PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics indicates an attempt to obscure the true destination or leverage compromised infrastructure. While no scripts were explicitly extracted, the nature of PDF malware often involves JavaScript for obfuscation or redirection, hence the inclusion of T1059.007.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 https://laborke.ru/uplcv?utm_term=how+to+pass+arraylist+in+intent+in+android PDF link annotation
    • http://electronicaindex.nl/images/uploads/41287544070.pdfIn PDF document text
    • http://irmascaritasdejesus.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/16145914e5af09---dawiv.pdfIn PDF document text
    • http://altadirezione-consulting.it/userfiles/files/duvis.pdfIn PDF document text
    • https://tectrongim.com/uploads/file/dejunimav.pdfIn PDF document text
    • http://sgrdpandher.com/userfiles/file/lutebabifupiduxemitufen.pdfIn PDF document text
    • http://vce34.ru/attachments/file/vizisixufesosujulafeneb.pdfIn PDF document text
    • https://cr2tek.com/userfiles/Proj_Name/files/25515394941.pdfIn PDF document text
    • https://stdtekstil.com/upload/ckfinder/files/5196944929.pdfIn PDF document text
    • http://addisonplaza.abwingsmd.com/uploads/files/savoj.pdfIn PDF document text
    • http://www.mtpartnersfl.com/wp-content/plugins/formcraft/file-upload/server/content/files/16147eac271476---sozezadatugudobegobo.pdfIn PDF document text
    • https://ddriu.hu/wp-content/plugins/super-forms/uploads/php/files/2de8525c2d11dc6b85d53993ebc25c4d/tavudopamasepasifuganib.pdfIn PDF document text
    • http://abovomedia.hu/_user/file/92779332599.pdfIn PDF document text
    • https://kaptenhoki.info/contents/files/71874153145.pdfIn PDF document text
    • https://www.mozartcantat.nl/wp-content/plugins/formcraft/file-upload/server/content/files/161505417bca6b---xivajuvozajedi.pdfIn PDF document text
    • http://gemmacapitalgroup.com/foto/file/reravuzutupagujukezejadab.pdfIn PDF document text
    • http://dekobonner.de/userfiles/file/11644262492.pdfIn PDF document text
    • http://www.iamgoingto1996.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e2f021419c---fekokikivijomorinez.pdfIn PDF document text
    • https://aceold.lrsinc.co/userfiles/file/gefisive.pdfIn PDF document text
    • http://euskararenginkana.eus/files/galeria/files/gowoxebegunikasitevujuwev.pdfIn PDF document text
    • https://www.kiakaha.gr/wp-content/plugins/super-forms/uploads/php/files/emns4h8hlc47t117n8aqinpr0u/kasukozu.pdfIn PDF document text
    • https://beauti-full.ru/uploads/files/50379546819.pdfIn PDF document text
    • https://tekstilkentrehber.com/upload/ckfinder/files/poduzudekepopewofoloraxa.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_off0000b134.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB134 17524 bytes
SHA-256: 81d31c2f8e769f7ede984771c3f28f7dbdb1bff193d5e6c8aea4efbc88b313e8
font_01_sfnt_off0000ddd4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDDD4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f5eb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5EB 10576 bytes
SHA-256: a5217b8b791ec1c73dae4cec2b81f0fcd1b446e82a5edfba6e88757015a13415

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