Malicious PDF — malware analysis report

Static analysis result for SHA-256 fe135bd96ad5005f…

MALICIOUS

PDF

43.5 KB Created: 2020-10-23 16:42:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-14
MD5: f8758b2493ab7d871e2e79260ec426f3 SHA-1: 82f691a2535ccea0a5a3b4b92259b8182c11495d SHA-256: fe135bd96ad5005f062795e58c09f2abddc76ae56d3a82aaf544b31f38fd2d81
184 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file contains a significant number of embedded links, with heuristics indicating it functions as a link farm. One of the embedded URLs, 'https://cctraff.ru/strik?keyword=th%25E1%25BB%25A7+t%25E1%25BB%25A5c+c%25E1%25BA%25A5p+c%252F+o+form+b', is flagged as a malicious redirector. The ML classifier also strongly indicated maliciousness. This suggests the document is part of an SEO spam or link farm operation intended to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

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.
  • 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?keyword=th%25E1%25BB%25A7+t%25E1%25BB%25A5c+c%25E1%25BA%25A5p+c%252F+o+form+b In PDF document text
    • https://cdn-cms.f-static.net/uploads/4367646/normal_5f87542a64760.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4374519/normal_5f8dc581189ac.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4368732/normal_5f89536dca776.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4383132/normal_5f92177fbfe67.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4366041/normal_5f8e11c8369aa.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4367277/normal_5f8a76ca35ce6.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4366982/normal_5f8db494d5681.pdfIn PDF document text
    • https://xojisige.weebly.com/uploads/1/3/1/6/131637148/f6b9193d1f016.pdfIn PDF document text
    • https://wevuviwujito.weebly.com/uploads/1/3/1/6/131636984/6538986.pdfIn PDF document text
    • https://guwomenod.weebly.com/uploads/1/3/0/8/130873843/tiladejonu.pdfIn PDF document text
    • https://gamupizesusaza.weebly.com/uploads/1/3/1/3/131398140/ketadovaguve.pdfIn PDF document text
    • https://vuxarujetununo.weebly.com/uploads/1/3/4/4/134437765/4637828.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/25ba8548-b595-43aa-a361-5a80a4980a81/98251101901.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/919a74a5-0364-4759-a118-80b1de33e9ed/95546049265.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/69adf85e-83b3-4f3d-a6a2-3692989fed30/used_book_stores_peoria_az.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/fe91ab3a-4ddf-4997-9014-b9bed0d9b3e8/xifevinutafavirifokud.pdfIn PDF document text
    • https://s3.amazonaws.com/pazifetanegapu/epidemiologia_del_cancer_de_mama_en_mexico.pdfIn PDF document text
    • https://s3.amazonaws.com/zuxadol/alphabet_arabe.pdfIn PDF document text
    • https://s3.amazonaws.com/vatosolikijike/40202262016.pdfIn PDF document text
    • https://s3.amazonaws.com/kavitokolezub/pdf_file_opener_free_download_for_pc.pdfIn PDF document text
    • https://s3.amazonaws.com/henghuili-files/vixirovomibig.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_off0000678c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x678C 5476 bytes
SHA-256: 11918276f67eda6ac4ee95726ccaa23ed7c798a625be9d525c7bffc7b2925d55
font_01_sfnt_off000079a3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x79A3 10792 bytes
SHA-256: 604e7000813a32b75de476d2087e36d9c8ef6a9d1a153dcf2a31576d994c74fc