Malicious PDF — malware analysis report

Static analysis result for SHA-256 a4c6b6544d008a85…

MALICIOUS

PDF

70.4 KB Created: 2020-12-27 17:51:00 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-20
MD5: bf9397c7773bd2b8fdd3037ef6277021 SHA-1: b0542b1c0405e71c4a6238c456be61005e58034b SHA-256: a4c6b6544d008a859be860212c437a6c136fcd479cfd7c895acb08fbf4b0ac74
194 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

The PDF contains multiple embedded links, including one pointing to a known malicious redirector. The heuristic PDF_MALICIOUS_REDIRECTOR_LINK and PDF_SEO_LINK_FARM indicate a large number of links designed to lead users to potentially harmful sites. The ML classifier also strongly flagged this PDF as malicious. The document body, though heavily obfuscated, contains metadata suggesting it was generated by wkhtmltopdf, a tool sometimes used to create malicious PDFs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • Image lure linking to an SEO redirector (free-download phishing) high PDF_SEO_UTM_REDIRECTOR_LINK
    PDF embeds an image with little or no body text and a clickable link to a multi-word utm_term / FeedBurner-proxied SEO redirector — the 'free ebook / solution-manual / document download' phishing family that ranks for natural-language search queries and routes the user into a payload/redirect chain. The PDF carries no exploit; the risk is the linked destination. Flagged structurally (image lure + SEO redirector) so it does not depend on a ClamAV/ML signature, and regardless of how many filler text pages the lure carries.
  • 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://cctraff.ru/aws?utm_term=fancy+pants+adventure+3++pc In PDF document text
    • https://cdn-cms.f-static.net/uploads/4474719/normal_5fa66198df792.pdfIn PDF document text
    • https://wubabenababi.weebly.com/uploads/1/3/4/4/134432193/topokom_dofan.pdfIn PDF document text
    • https://tamatopufav.weebly.com/uploads/1/3/4/3/134386909/05067773f4e57ae.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4477386/normal_5faa49b0d1ea1.pdfIn PDF document text
    • https://kukezuleji.weebly.com/uploads/1/3/4/3/134361302/tawujez-nobadena.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4368975/normal_5fbee3b213562.pdfIn PDF document text
    • https://namobilezivi.weebly.com/uploads/1/3/1/8/131857476/tamezi.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4415530/normal_5fe829d6c0af8.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4489846/normal_5fe2ac7e09a0b.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/3bf9dead-12e5-46b1-8f5e-3e3cd5b1f4a0/nuvudolawob.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/eb21b147-16ee-4b87-8abe-b06d175262ea/no_min_woo_actor.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/7e1f6641-260d-41ea-b993-fe6197811ab4/62851140413.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/c1139dfa-98c1-43af-b1d9-ebbdb428678a/32895701683.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/c4e5c344-6977-4fed-9de5-f27946b863f9/mimuroruxegepozevaneb.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/57900cdf-f3dd-4ab2-beec-45e57cf75338/craftsman_table_saw_manual.pdfIn 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
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c0ea.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC0EA 5316 bytes
SHA-256: 07155a2852f4a684e4db4ada7009878632aeca46afa2578cbf3d3e3e285aa2a5
font_01_sfnt_off0000d31e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD31E 10468 bytes
SHA-256: 2b1994765830f9156836b62999057ce3a784e534783e68a10fda3f7dafa9a427
font_02_sfnt_off0000f725.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF725 16164 bytes
SHA-256: d781c508aaf473e50263a6aabc3f4161b7fa10724c54bb8d35addee38a7f1c44

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