Malicious PDF — malware analysis report

Static analysis result for SHA-256 1d7f9b23bc5b3336…

MALICIOUS

PDF

94.2 KB Created: 2021-09-04 02:54:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 4305416ff389347ed5c5d6c4a0337239 SHA-1: ac21f0c7848a564fc3d9ec53254da9fbeab88747 SHA-256: 1d7f9b23bc5b3336823e2b637e4be72ecab687a2f3c4fe66a838f490c0c1a0f2
156 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm hosted on disposable domains, with multiple URLs pointing to PDF files. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for human readability but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9988

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 http://aurora-c.jp/files/files/kupazolesiliwazawuju.pdf In PDF document text
    • https://phase1acoustics.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b91227ee542---2823647132.pdfIn PDF document text
    • http://lubrifianti-auto.ro/files/file/42366367909.pdfIn PDF document text
    • http://www.socalgreatwhite.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609b6998ecc9c---ripusodu.pdfIn PDF document text
    • http://www.holzbau-hoelzl.at/wp-content/plugins/formcraft/file-upload/server/content/files/160b22ba12372b---duliririgojubexozimo.pdfIn PDF document text
    • http://www.elstar.ru/uploads/files/retopokogabexa.pdfIn PDF document text
    • https://vayamcs.com/content_files/files/fukududokepevave.pdfIn PDF document text
    • http://www.hptindia.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607da1ae53da1---gipide.pdfIn PDF document text
    • https://lokmangal.co.in/wp-content/plugins/super-forms/uploads/php/files/dde1d44b6d4bdc15cf147cd5a0f705e9/82196588715.pdfIn PDF document text
    • https://www.americanapi.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609a82f4b5675---30235456295.pdfIn PDF document text
    • http://mikailang.net/userfiles/file/20210503214851_2101201986.pdfIn PDF document text
    • http://linyuepharm.com/upload/files/xoxifir.pdfIn PDF document text
    • https://halobysciton.com/wp-content/plugins/formcraft/file-upload/server/content/files/160759af01d19f---wejotenabi.pdfIn PDF document text
    • https://expobar.vn/app/webroot/files/images/pages/files/puxagisaxadawejogiriju.pdfIn PDF document text
    • http://driscollandgibson.com/images/edit_images/file/57055985699.pdfIn PDF document text
    • http://lab4050.com/upload/editor/file/nizuminagogewinuvit.pdfIn PDF document text
    • http://diakmelo.hu/ckfinder/userfiles/files/48003254440.pdfIn PDF document text
    • https://novahealthclinic.ca/userfiles/file/tixopese.pdfIn PDF document text
    • https://chicagoportablexray.com/wp-content/plugins/formcraft/file-upload/server/content/files/160949232dcf5e---jakijixuxarudetewokazivo.pdfIn PDF document text
    • http://charivne.info/images/file/biwedepes.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/GLLx1DTH0VQ/uplcv?utm_term=kahalagahan+ng+komunikasyon+pdfPDF 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://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_off00010d68.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D68 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0001257a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1257A 17156 bytes
SHA-256: 23f5a3cf3ce57fbb2dd2fdf0bdba67db4995e0c4058d778d9b089697d56795b1
font_02_sfnt_off00015253.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15253 10912 bytes
SHA-256: b545da3e8c472f560c24032cb2a5ea591c5f37b9811f6a2609e50ea336368a96

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