Malicious PDF — malware analysis report

Static analysis result for SHA-256 91ff5da3f2e78ca2…

MALICIOUS

PDF

71.3 KB Created: 2021-06-19 14:17:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-27
MD5: f7664ce678c735598050461010150812 SHA-1: c8348e6960f7f05d929ecf2dadf51179c677ae01 SHA-256: 91ff5da3f2e78ca239b10776c427b7a96156bbf5199fa25d2012dc266d412ec4
94 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF document contains a link farm pointing to multiple compromised WordPress sites, likely intended to redirect users to malicious content. The ML classifier also flagged this PDF as malicious. No scripts were extracted, and the document body was heavily obfuscated, preventing a more detailed analysis of the specific lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.8179

Heuristics 4

  • 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
  • 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://directprocessors.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c37697db65f---61851011186.pdf In PDF document text
    • https://monuments-msk.ru/wp-content/plugins/super-forms/uploads/php/files/6669017c8e4a4081e1042f4a5103c278/wubavik.pdfIn PDF document text
    • http://diagonal.org.ar/wp-content/plugins/formcraft/file-upload/server/content/files/1606cba2f3435a---10527830382.pdfIn PDF document text
    • https://steklo-shik.ru/userfiles/file/12793117187.pdfIn PDF document text
    • https://vetranhtuongmamnon.vn/wp-content/plugins/super-forms/uploads/php/files/gsdtldfjb8bjkfohenoq4rhfbs/66314077022.pdfIn PDF document text
    • https://www.northernillumination.com/wp-content/plugins/super-forms/uploads/php/files/e08f23afd1b25ba0bcef3ff188fcc68f/47640813339.pdfIn PDF document text
    • https://www.acptechnologies.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f7c542d4a6---21952818906.pdfIn PDF document text
    • http://ttlengenharia.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1607200395eede---ralosipepuneviweken.pdfIn PDF document text
    • http://sosnovgeo.ru/userfiles/file/55614384603.pdfIn PDF document text
    • http://nmglyxx.com/userfiles/file/zidifaxabaporalukonuwuw.pdfIn PDF document text
    • http://amoy-art.com/Upload/file/nosapava.pdfIn PDF document text
    • http://stlnsk.ru/uploads/file/voxujideliduxusub.pdfIn PDF document text
    • http://www.gainerwindows.ca/wp-content/plugins/super-forms/uploads/php/files/pdm9l7uk78pcnp0bhs5j8gfj53/fejikumif.pdfIn PDF document text
    • http://gorisum.net/fckeditor/upload_file/file/84692286115.pdfIn PDF document text
    • https://endoaccessories.com/wp-content/plugins/super-forms/uploads/php/files/33h3vc0prun7gbgd1t2sdoupmi/7335524039.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/Uplcv/~3/3vuEKuznOb8/uplcv?utm_term=witcher+1+silver+swordPDF link annotation
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f203.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF203 5032 bytes
SHA-256: fa5772ba33e5d28e7ccb48898470e2bace8a859d715fc8763ac6c060c812e54b

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