Malicious PDF — malware analysis report

Static analysis result for SHA-256 66c4f7aca04b5f78…

MALICIOUS

PDF

75.1 KB Created: 2021-06-10 03:11:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-29
MD5: 4b1473ac5e9f820864b2801846a28ec0 SHA-1: adac4e65724fc57c32869976552ea83f780601ec SHA-256: 66c4f7aca04b5f781d5c39e71658169687e1c289f284bfed09d8b8580187b943
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF file is identified as malicious by ML classifiers and ClamAV, indicating it is likely a phishing or trojan delivery mechanism. It contains numerous embedded links, many pointing to compromised CMS uploads, suggesting a link farm designed to redirect users to malicious content. The document body, though heavily obfuscated, appears to be a lure disguised as an educational worksheet.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://archism.ru/uplcv?utm_term=comprehension+worksheet+for+grade+7 PDF link annotation
    • https://alenakovalchuk.ru/wp-content/plugins/super-forms/uploads/php/files/1212cd446af6ac377d48479613b7052c/pogojajelagovimaf.pdfIn PDF document text
    • http://vibrosystem.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160beed73a12d3---papolago.pdfIn PDF document text
    • http://www.zaluziemalina.cz/userfiles/file/ridosu.pdfIn PDF document text
    • http://nc2e.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1607e227c23841---jomotosolo.pdfIn PDF document text
    • http://www.primalegal.eu/wp-content/plugins/super-forms/uploads/php/files/9v4570jkiaa23pag4bm4jin0o6/gudogudesusiruzola.pdfIn PDF document text
    • https://coloreverything.love/wp-content/plugins/super-forms/uploads/php/files/69c9b4003cd40e5590c2303604325595/rudifozolofonewagebedo.pdfIn PDF document text
    • http://elonsummerstorage.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c13ee9ecc08---26759545216.pdfIn PDF document text
    • https://nanyangtextile.com/userfiles/file/nifinurenidi.pdfIn PDF document text
    • http://texasstatealphaxialumnae.com/clients/f/fe/fe72632f573fdc77cca6b85875c63e8a/File/moneranasi.pdfIn PDF document text
    • https://www.truesdalepainting.com/wp-content/plugins/formcraft/file-upload/server/content/files/160700959499b1---75914959989.pdfIn PDF document text
    • https://cutletsmeat.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606d25b56effd---kumavijibabuv.pdfIn PDF document text
    • https://activepymes.com/pub/file/36706857354.pdfIn PDF document text
    • https://wentworthre.com/wp-content/plugins/super-forms/uploads/php/files/c5f30509e86c9a86c3c513eb718a02c2/xekapome.pdfIn PDF document text
    • https://hotelritariccione.it/wp-content/plugins/formcraft/file-upload/server/content/files/16083c6816bd6d---pitoluluzax.pdfIn PDF document text
    • http://indiebookoftheday.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a32e62a438a---wefojifomojovara.pdfIn PDF document text
    • https://vuaship.com/wp-content/plugins/super-forms/uploads/php/files/u8cjletl4r8vdp2qubiioc02pn/vesoxedamixawuj.pdfIn PDF document text
    • http://www.blackhillsdancecentre.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607760c7022e2---65914124989.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_off0000e786.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE786 5564 bytes
SHA-256: a59aed68584a4cdbf4baf970d98322c7943de9315e267492c348211eaf6b4be8
font_01_sfnt_off0000fa5d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA5D 11168 bytes
SHA-256: 8fe86f7c4c2302c8b7898dc5da2c4b36279fa56508f755065ef96b4ff38d4466