Malicious PDF — malware analysis report

Static analysis result for SHA-256 36d61f5716b0f43a…

MALICIOUS

PDF

114.1 KB Created: 2021-03-30 05:41:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-21
MD5: 319c5ba3bd2c627cf868cdac6e001518 SHA-1: 65f95d4bd41673696c093d2769a7630683b76ab1 SHA-256: 36d61f5716b0f43a167acaf9cfb6713c569a8fabce4ecf310f5d39106eb09b4f
186 Risk Score

Malware Insights

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

The PDF contains numerous external links, identified as a link farm, with one prominent URL pointing to a domain associated with SEO spam. The ML classifier and ClamAV detection strongly indicate malicious intent. While no scripts were explicitly extracted, the PDF structure and heuristic firings suggest it's designed to redirect users to potentially malicious or spammy content, aligning with phishing or SEO manipulation tactics.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9962

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/award?keyword=hypertension+treatment+pdf PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4392864/normal_603823cbea550.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4447434/normal_6062659e1da80.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4485711/normal_6007133593f5f.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4365601/normal_6047b672b9504.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4458394/normal_6056bc2308a7e.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4445557/normal_605fa93b8a4e9.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4464850/normal_5fd79672a714c.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4379611/normal_601bd749d81b9.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4372681/normal_6045fb606ee82.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://8a833fea-7c9a-4d2e-a5a7-d3590f42a3e5.filesusr.com/ugd/9aab09_11b5a8a1478c4a629bbd50b333da87f8.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/jevopemosod/composition_of_functions_worksheet_5_answers.pdfIn PDF document text
    • https://63209029-b609-4f89-80e5-af59b408cdb4.filesusr.com/ugd/0713e6_80921018244d4565adee2c1a21ee8ebc.pdf?index=trueIn PDF document text
    • https://4bf641bf-117a-4913-931f-55e49063997f.filesusr.com/ugd/5befcb_43fc2f4184be40558df53f7225c6b0a1.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/jevelel/vosadakavawuxotilar.pdfIn PDF document text
    • https://s3.amazonaws.com/perurulexi/tawunenijesina.pdfIn PDF document text
    • https://101c3d73-5e22-4da1-a203-a3a2a794ce88.filesusr.com/ugd/69a512_411d2a4ed44d4959b72084fac9f24bf0.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/lizuseguwix/platformio_arduino_uno.pdfIn PDF document text
    • https://s3.amazonaws.com/selivuvumepaveb/5933956275.pdfIn PDF document text
    • https://d78d2789-9aef-4bfd-88be-9093bec910ef.filesusr.com/ugd/87a178_634b7c60cd0544a0aa6bfc54e9508bde.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/ladojenefe/vonavarukusudu.pdfIn PDF document text
    • https://s3.amazonaws.com/sojebelevenex/the_endless_trailer_ita.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_off00018253.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x18253 5220 bytes
SHA-256: 0c1d03f1c2023ec8555055defdc95e0d662e4480f40064ece35d6d19dfd930af
font_01_sfnt_off00019409.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x19409 11824 bytes
SHA-256: 5cb0c3c35ae5e98f392a1cf4e1b1f4dc098bf0fc272fa05d3aef1f482a6d6473