Malicious PDF — malware analysis report

Static analysis result for SHA-256 4fdefa41ebcf3dde…

MALICIOUS

PDF

68.8 KB Created: 2020-11-17 19:03:49 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-27
MD5: 27f613bf84230fdc6d6aeecc5207c77a SHA-1: 7f038a8e94e6ab4fd4455020508396ad6097892e SHA-256: 4fdefa41ebcf3ddef38c6f4250e5c0e444056bea1588ba3cc7d8542478db57f9
244 Risk Score

Malware Insights

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

The PDF file contains a large number of external links, many hosted on disposable domains, characteristic of a link farm. One of the embedded URLs, 'https://cctraff.ru/strik?utm_term=xyz+homework+answers', is identified as a malicious redirector. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or malware distribution.

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
  • 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.
  • 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.
  • 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/strik?utm_term=xyz+homework+answers In PDF document text
    • https://cdn-cms.f-static.net/uploads/4380079/normal_5f8ce91313565.pdfIn PDF document text
    • https://rabidibizuzej.weebly.com/uploads/1/3/4/6/134648686/512ecfd2b94b.pdfIn PDF document text
    • https://suxokigivulumu.weebly.com/uploads/1/3/4/4/134479742/xobinusiguj.pdfIn PDF document text
    • https://vodexekuteb.weebly.com/uploads/1/3/0/7/130776001/nikusuz.pdfIn PDF document text
    • https://jaxuwigoba.weebly.com/uploads/1/3/4/2/134266140/21f56645.pdfIn PDF document text
    • https://zoxuzula.weebly.com/uploads/1/3/4/4/134489613/d21083f5b.pdfIn PDF document text
    • https://zetidikusas.weebly.com/uploads/1/3/4/7/134740093/4865428.pdfIn PDF document text
    • https://fiwadevu.weebly.com/uploads/1/3/4/5/134592392/miloxopaji.pdfIn PDF document text
    • https://weziriditovi.weebly.com/uploads/1/3/4/1/134108838/keviper_resefejaguka_liwax_sopurigeza.pdfIn PDF document text
    • https://pinukavuzufov.weebly.com/uploads/1/3/4/3/134307945/xugapuv.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/3c04d458-1bc3-4ae1-a6dc-c76ed4b88cb0/75534705305.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

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d237.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD237 5176 bytes
SHA-256: 895a4e3c613ead95a007ac9abf02084eca5797a2419dad2dccfb4fa1c012a5ba
font_01_sfnt_off0000e3bd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE3BD 10332 bytes
SHA-256: 83d66abe6331d4427a0b6f8f7756e24b245c03f74ec5b44bd25624468861233a

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