Malicious PDF — malware analysis report

Static analysis result for SHA-256 c6a8caf6147c7621…

MALICIOUS

PDF

81.1 KB Created: 2021-06-19 04:58:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-05
MD5: 5a802c0df76a1b20f3ad2a40e364c0f3 SHA-1: 924d46e21d4f4e68414f947b16b8811d5e970f4f SHA-256: c6a8caf6147c7621ddf7f3936394d1d3fee29e403b0dc0cce69924563d9336a0
156 Risk Score

Malware Insights

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

The file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It functions as a link farm, with numerous embedded URLs pointing to compromised WordPress sites, suggesting a phishing or malware distribution scheme. The document body is heavily obfuscated and contains metadata from wkhtmltopdf, but the primary threat lies in the external links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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://infrive.ru/uplcv?utm_term=types+of+nut+and+bolt+pdf PDF link annotation
    • https://dacoma.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16074736f723e7---kutaxivik.pdfIn PDF document text
    • http://www.mondzorgvesa-voorschoten.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1608d73eea79ae---kunopa.pdfIn PDF document text
    • https://aduanaldelvalle.com/userfiles/file/nugagalaxuzalanato.pdfIn PDF document text
    • https://appfacile.it/file/zixusub.pdfIn PDF document text
    • http://www.iycadana.org/wp-content/plugins/super-forms/uploads/php/files/eth7em0t1unikdcrunlle7nv76/subop.pdfIn PDF document text
    • http://tiramisu-o.com/yamituki-n/uploads/files/mederelisarudukowikame.pdfIn PDF document text
    • http://klpa.net/userData/board/file/dupekatukaxubawozovefef.pdfIn PDF document text
    • http://deurwater.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b1b856013fc---ribem.pdfIn PDF document text
    • https://www.hagensmarketing.com/wp-content/plugins/formcraft/file-upload/server/content/files/16078924f5007e---bosigaxezuxud.pdfIn PDF document text
    • http://www.meglobalinc.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160a8da1edd1ed---58403372958.pdfIn PDF document text
    • https://angkagenap.com/contents//files/jejobaduxanogafamogedaguz.pdfIn PDF document text
    • https://perleyparish.org/wp-content/plugins/super-forms/uploads/php/files/3fd8e8c450d820a3065860ba4f24cce7/81992669910.pdfIn PDF document text
    • https://divinesacredshakti.com/wp-content/plugins/super-forms/uploads/php/files/df3c3475ad489c0a20d5b099d11a821f/bigid.pdfIn PDF document text
    • https://laihouston.com/wp-content/plugins/super-forms/uploads/php/files/087b25ec325d94a42687bc9caf8f457b/36642820350.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_off0000ff68.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF68 5132 bytes
SHA-256: 79d7867d25f64a82c7a7ab72e2122aa432d5bad80df695378382494cbaac12de
font_01_sfnt_off000110f7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x110F7 11408 bytes
SHA-256: d04426f346f577eb806de5c3d06d3e1eea43b70cb921c26e9748845546485bee

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