Malicious PDF — malware analysis report

Static analysis result for SHA-256 c99bc904fff0a454…

MALICIOUS

PDF

75.2 KB Created: 2021-05-21 05:43:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2026-06-04
MD5: fd2010b7a71b9ada66ab6c0aee435944 SHA-1: 229abf2269ec3664db5276c583a40e9238c2d4d1 SHA-256: c99bc904fff0a454f3e3750bdfca1388d7e23f7b14561e6156f1ab89f91eaa01
196 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

The PDF contains numerous external links, many of which are part of an SEO link farm, and one specifically uses a UTM parameter to redirect to 'vilenefex.ru'. This indicates a phishing or malware distribution attempt. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing lures.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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
  • 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.
  • 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://vilenefex.ru/strik?utm_term=brokeback+mountain+story+pdf PDF link annotation
    • https://tejebufu.weebly.com/uploads/1/3/4/3/134353082/e4ce15.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4403418/normal_5fc9fe8b4888a.pdfIn PDF document text
    • https://s3.amazonaws.com/xapidajovaji/descent_of_man.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4417986/normal_5fdd1a9961774.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4479674/normal_60539d7b31e11.pdfIn PDF document text
    • https://s3.amazonaws.com/tozaduliwubega/p_o_c_bible_malayalam.pdfIn PDF document text
    • https://s3.amazonaws.com/pibajuwi/mepuzikan.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4481406/normal_605f58158e60a.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4469116/normal_601739484d9d3.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4444356/normal_606819e4d34b5.pdfIn PDF document text
    • https://s3.amazonaws.com/fogibi/criminal_law_amendment_act_2013_india.pdfIn PDF document text
    • https://s3.amazonaws.com/tarizirefevifab/58634589287.pdfIn PDF document text
    • https://bekefipupo.weebly.com/uploads/1/3/4/0/134096026/7aa33b184c3f.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4480580/normal_602c431bbea32.pdfIn PDF document text
    • https://s3.amazonaws.com/mamibis/bromate_formation_water_treatment.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4372673/normal_6011714b0d0cb.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4487399/normal_601db82c81c5e.pdfIn PDF document text
    • https://s3.amazonaws.com/minegikukovel/kazakhstan_temir_zholy_annual_report.pdfIn PDF document text
    • https://s3.amazonaws.com/luropiw/fazaf.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4369191/normal_605ef728bcf3f.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

Related samples 8

Ranked by shared artifacts, heuristics, extracted URLs, CVEs, and signatures.

Full JSON: related samples API

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e765.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE765 5624 bytes
SHA-256: a521edf8810d9a539c37fd89e584a24e72e3b5510386420976e90f8b2738a087
font_01_sfnt_off0000fa7c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA7C 11140 bytes
SHA-256: c1b44256302b8a1546182df3538490b4c006f52b61eeb40a8f6c3ca8e54ada7b

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