Malicious PDF — malware analysis report

Static analysis result for SHA-256 1c91c6e773a5ebe7…

MALICIOUS

PDF

71.1 KB Created: 2021-02-27 01:34:57 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-06-04
MD5: b3d28900dd6e5349624505a1a2fcc494 SHA-1: a43e1eaac2a34ae76a4bc3d5bccd31e6790f575b SHA-256: 1c91c6e773a5ebe768b76f9793d313ba66f72e513e7536d8ede61206fd576067
186 Risk Score

Malware Insights

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

This PDF file is identified as malicious by multiple heuristics and a machine learning classifier, and is also detected by ClamAV as a phishing trojan. It functions as a link farm, containing numerous external URLs pointing to other PDF documents hosted on disposable domains. The primary purpose appears to be SEO manipulation or distributing further malicious content through these linked PDFs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9995

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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.
  • 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://kuzutuzo.ru/aws?utm_term=10+electronic+components+and+their+symbols PDF link annotation
    • https://gakezepatirana.weebly.com/uploads/1/3/2/7/132712251/3283019.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4413122/normal_600e3ff50ca48.pdfIn PDF document text
    • https://cdn.sqhk.co/netimawifes/Xbzq4Hv/amazon_seller_central_uk_fees.pdfIn PDF document text
    • https://cdn.sqhk.co/satofurijob/fhcieih/alan_walker_faded_singer.pdfIn PDF document text
    • http://xemizawufogutuf.scienceontheweb.net/20439407045.pdfIn PDF document text
    • https://dubonizu.weebly.com/uploads/1/3/1/6/131606556/8aa896c71f9d7.pdfIn PDF document text
    • https://wunovolal.weebly.com/uploads/1/3/5/3/135311751/somopufewa.pdfIn PDF document text
    • https://cdn.sqhk.co/nadipozow/lji9fha/color_hop_3d_download.pdfIn PDF document text
    • https://nivujetomut.weebly.com/uploads/1/3/4/7/134753784/ef5dc74.pdfIn PDF document text
    • https://ginugifugebiner.weebly.com/uploads/1/3/4/2/134234672/0455371763e9f07.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_off0000d959.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD959 5656 bytes
SHA-256: df65e62cd7ff68f490081105d099386255792eb8664f214b0720e3dad12898c1
font_01_sfnt_off0000ec63.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC63 10252 bytes
SHA-256: 95c4ffd2bdf49a899961a4e2b85e22aa613389fd70e5a07c7931725b97437d36

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