Malicious PDF — malware analysis report

Static analysis result for SHA-256 838af9b58befe716…

MALICIOUS

PDF

62.0 KB Created: 2021-06-23 18:52:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-23
MD5: d551218adb1f08c092e79f895c8493fe SHA-1: 8aaf709aaaf82ff7274e7f6ce425283bae4c156e SHA-256: 838af9b58befe7161c92ba2d488da628eef63a066bc45f2ba4379cde8d89e017
96 Risk Score

Malware Insights

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

The PDF contains numerous links pointing to compromised websites and disposable hosting, indicating a link farm designed to redirect users to malicious content. The ML classifier strongly flagged this PDF as malicious, and the presence of multiple external URIs suggests an attempt to lead the user to a secondary malicious resource. No scripts were extracted, but the overall structure and URL distribution are indicative of a phishing or malware distribution lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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://deesudcoolingtower.com/userfiles/file/74031604332.pdf In PDF document text
    • http://www.canadavisaservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/16082311f491b4---42645853773.pdfIn PDF document text
    • http://mas.vacations/wp-content/plugins/formcraft/file-upload/server/content/files/1607212483a510---86305814893.pdfIn PDF document text
    • https://wills.sg/wp-content/plugins/super-forms/uploads/php/files/5ec65c018c7dd3d5b920db743ade86fd/70087263675.pdfIn PDF document text
    • https://computerzone.pk/file/dirifujidowizawomifasoto.pdfIn PDF document text
    • https://www.helpagesl.org/wp-content/plugins/formcraft/file-upload/server/content/files/16086c062b2350---wetuwatuvemijuvovesokud.pdfIn PDF document text
    • https://lsp.od.ua/wp-content/plugins/super-forms/uploads/php/files/3p9jlgq8pb08jp8011q0vh7ri6/lomojunukila.pdfIn PDF document text
    • http://biotledlight.com/userfiles/file/%5C/30626834272.pdfIn PDF document text
    • http://inarchengineering.it/userfiles/files/54952120270.pdfIn PDF document text
    • http://dambi.pl/userfiles/file/27115091480.pdfIn PDF document text
    • http://carroll1975.com/clients/4/4e/4e2b018d07aaa5a30c3e4fca1c7a8df7/File/57843519910.pdfIn PDF document text
    • https://www.alongsideasia.com/wp-content/plugins/super-forms/uploads/php/files/5f293815a90e99b60ecfbf5e7054fc98/66437253120.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/GLLx1DTH0VQ/uplcv?utm_term=algorithms+unlocked+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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b173.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB173 5412 bytes
SHA-256: c264766e9c6836c595f51c98dcfeb40d855966dddb60d7e91108cb9ebe3d4152
font_01_sfnt_off0000c3bd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC3BD 11612 bytes
SHA-256: 65916e54dd1d046a5bfff7b7d26c989ddc9f632adee58c60fe4f1bb1c85dc456

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