Malicious PDF — malware analysis report

Static analysis result for SHA-256 3a3080e2643bac47…

MALICIOUS

PDF

78.1 KB Created: 2021-09-20 11:44:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 588a331af4e81103aa842a1a1fcd1dda SHA-1: e95e0e05bb0d3b3804fe881caf042c6526c46f1c SHA-256: 3a3080e2643bac47de6e7188edaa71fb900da9f138d29bd78612deb57f709915
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which point to external PDF files hosted on various domains. Several heuristics indicate this is a link farm, with some links pointing to compromised CMS upload storage. The ML classifier strongly flagged this PDF as malicious. While no scripts were directly extracted, the nature of the embedded links suggests a malicious intent to redirect users to potentially harmful content or for SEO abuse.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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 http://e-junghan.com/userData/board/file/ligas.pdf In PDF document text
    • https://nutstudio.it/userfiles/file/nunurewikuparomatuj.pdfIn PDF document text
    • https://byocamacho.com/ckfinder/userfiles/files/tarinilezafaguwoparibalu.pdfIn PDF document text
    • https://xn--23-6kci4asohe8k.xn--p1ai/userfiles/file/fetufizazutunak.pdfIn PDF document text
    • https://ijpdua.com/contents/files/81288116196.pdfIn PDF document text
    • http://inspirationallabels.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1613b4650d03d3---10320125788.pdfIn PDF document text
    • http://gallery4walls.com/upload/editer/file/rogixalovelisogu.pdfIn PDF document text
    • https://harpethvalleyhealth.com/wp-content/plugins/super-forms/uploads/php/files/9aa7729b9eba7fd6c23237b8c8375597/tuven.pdfIn PDF document text
    • http://hotelgiottotorino.com/userfiles/files/nuleladixamug.pdfIn PDF document text
    • http://www.predia.cz/userfiles/file/sazarikixap.pdfIn PDF document text
    • http://csc0731.com/userfiles/file/20210911055745_wb3g0e.pdfIn PDF document text
    • http://dcbestwings.com/uploads/files/mugorumiribumo.pdfIn PDF document text
    • http://medeeatour.ro/mm/file/55615687996.pdfIn PDF document text
    • https://www.ediliziaindustriale.com/wp-content/plugins/formcraft/file-upload/server/content/files/161418496ca9b6---votegefego.pdfIn PDF document text
    • https://onlineadda.net/ckfinder/userfiles/files/fifeluvukopiwifo.pdfIn PDF document text
    • https://proia.bg/userfiles/file/48190139602.pdfIn PDF document text
    • http://zrdb-drogbud.pl/Upload/file/97427228757.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/GLLx1DTH0VQ/uplcv?utm_term=logic+puzzle+games+androidPDF 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_off0000cf2b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCF2B 10876 bytes
SHA-256: a47e76739078062c37c51b91b381d06bb0e1612b66a78fcfcdb0a388a55ed369
font_01_sfnt_off0000e80c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE80C 16420 bytes
SHA-256: 69029739431b76870e0788528d2003d9f90fc773672bf3a48a6e980c973012c8
font_02_sfnt_off000112c9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x112C9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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