Malicious PDF — malware analysis report

Static analysis result for SHA-256 1caece5d8ba1b60f…

MALICIOUS

PDF

79.5 KB Created: 2021-06-13 21:06:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-11
MD5: ccd0c657222eef44ae501931a86d5c08 SHA-1: c3d52ee8e76faf24af18176442fef9f8e54a9045 SHA-256: 1caece5d8ba1b60f40f894e0aca4ad8cbb834dc1f8e673936e4a55bce51562c7
156 Risk Score

Malware Insights

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

The PDF contains a link farm designed to direct users to download free textbooks, leveraging compromised WordPress sites and disposable domains. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or malware distribution. No scripts were extracted, but the PDF structure and URL patterns are consistent with a phishing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://krisoc.ru/uplcv?utm_term=places+to+download+textbooks+for+free PDF link annotation
    • https://acrgroup.nl/userfiles/file/61356261352.pdfIn PDF document text
    • https://frennphotography.com/wp-content/plugins/formcraft/file-upload/server/content/files/16096d03f97038---10165745010.pdfIn PDF document text
    • http://aircond.md/upload_fck/file/zekazidewuwamefu.pdfIn PDF document text
    • http://inspirationallabels.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160ab90235ca1a---lejijiveruwi.pdfIn PDF document text
    • https://leicht-spb.ru/wp-content/plugins/super-forms/uploads/php/files/f3082e678a55045a7016751483bcb89e/55446102334.pdfIn PDF document text
    • https://ozmutludokum.com/userfiles/file/bazivete.pdfIn PDF document text
    • https://activepymes.com/pub/file/kukegixiwesuwavofot.pdfIn PDF document text
    • https://www.costaverde.it/wp-content/plugins/formcraft/file-upload/server/content/files/1608063f441e3e---lezepu.pdfIn PDF document text
    • https://gz-topstar.com/wp-content/plugins/super-forms/uploads/php/files/8f1ee1fa4feb8dc2f8cf8b1e62bc9757/85065061722.pdfIn PDF document text
    • https://tkpmission.org/wp-content/plugins/formcraft/file-upload/server/content/files/160907fe25fada---kaxenufoxiwiraserovelipoj.pdfIn PDF document text
    • http://zovsh.com/Uploadfiles/files/59652164996.pdfIn PDF document text
    • http://lamachine.nl/userfiles/file/nulidutipisubawiponifodev.pdfIn PDF document text
    • http://www.radiopopiatej.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607aaac7cce60---48185670200.pdfIn PDF document text
    • http://uyaviation.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609e1fa3b7c85---61538677225.pdfIn PDF document text
    • https://www.mixedclass.com.au/wp-content/plugins/super-forms/uploads/php/files/v28hjp79u5srva26b7l0f93u0v/97781224279.pdfIn PDF document text
    • https://isleo.com/i_photos/file/35434011879.pdfIn PDF document text
    • https://www.prowallpanama.com/wp-content/plugins/super-forms/uploads/php/files/c848756cf5b882cc94a6cc369de646b2/65524681625.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_off0000f79e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF79E 5380 bytes
SHA-256: 1c3f3fbf4c2a34d0ffe665ac3ba787896739761cf68abfa80eb039d990021dbc
font_01_sfnt_off00010a0d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A0D 10840 bytes
SHA-256: ca199d857d27359d7b9219001b7a4b20fd7f5e43df4ad9a6cb571e4b72ceceed