Malicious PDF — malware analysis report

Static analysis result for SHA-256 52526c407e3f0504…

MALICIOUS

PDF

78.8 KB Created: 2021-05-28 21:09:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 388c3f542b9a28ea0d706458e7459c93 SHA-1: 755160d3d3e922d7b99c1be63ed20da4bbf0546e SHA-256: 52526c407e3f0504d3811851ec67107ba9b8a4d8631d509e7e1d59bb11e117b4
156 Risk Score

Malware Insights

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

This PDF file is identified as malicious by ML classifiers and ClamAV, indicating a phishing or trojan threat. It contains a large number of external links, many pointing to PDF files hosted on platforms like strikinglycdn.com and weebly.com, suggesting a link farm or SEO manipulation tactic to distribute malicious content. The primary malicious URL identified is vilenefex.ru, which is likely used to host or redirect to further malicious payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 5

  • 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.
  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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=physics+class+11+formula+sheet+pdf+in+hindi+download
    • https://static.s123-cdn-static.com/uploads/4492555/normal_5fe5569043f5b.pdf
    • https://cdn-cms.f-static.net/uploads/4482027/normal_600ae4f1376c7.pdf
    • https://zedasadexim.weebly.com/uploads/1/3/0/7/130775923/3283cd76539d.pdf
    • https://mabexerezigija.weebly.com/uploads/1/3/5/3/135324341/vivanosiki.pdf
    • https://cdn-cms.f-static.net/uploads/4384301/normal_602fec535e0f0.pdf
    • https://cdn-cms.f-static.net/uploads/4420030/normal_6011d777c5c6f.pdf
    • https://geputugu.weebly.com/uploads/1/3/5/3/135311163/kabanasaxodofava.pdf
    • https://static.s123-cdn-static.com/uploads/4481408/normal_5ffef262e6eda.pdf
    • https://jobexevufurol.weebly.com/uploads/1/3/4/5/134526996/c9e9aa37.pdf
    • https://rosokejasos.weebly.com/uploads/1/3/1/8/131871530/lizosa.pdf
    • https://cdn-cms.f-static.net/uploads/4373008/normal_6059efdeb0491.pdf
    • https://mugunerer.weebly.com/uploads/1/3/4/4/134479547/1dba138cf7.pdf
    • https://ninofupefuf.weebly.com/uploads/1/3/1/8/131856131/5139821.pdf
    • https://static.s123-cdn-static.com/uploads/4477626/normal_5fe25d97d6cb1.pdf
    • https://cdn-cms.f-static.net/uploads/4529024/normal_6011ef4b8a149.pdf
    • https://vetenejoxo.weebly.com/uploads/1/3/1/3/131379321/lavamomimotet.pdf
    • https://resuzomesidi.weebly.com/uploads/1/3/4/7/134746605/2893471.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://uploads.strikinglycdn.com/files/c085790c-1b1e-4823-a64c-04688b6e70e5/81475048554.pdf
    • https://uploads.strikinglycdn.com/files/11f1fffe-68a0-4306-bced-11d91d2477de/table_o_f_critical_values.pdf
    • https://uploads.strikinglycdn.com/files/e592f139-4d1b-4dc5-8fba-90582707f70d/resumen_del_libro_tus_zonas_erroneas_por_capitulos.pdf
    • https://uploads.strikinglycdn.com/files/c9184571-ca98-465d-b946-cc9d1c4a9ae3/andy_stanley_starting_point_1.pdf
    • https://uploads.strikinglycdn.com/files/f60ad8c0-1b68-4e39-895b-74daaf34fdc5/network_topology_slideshare.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f210.bin
dbd81d0c3dc3719e5ee6e74dbc8c0d27006b22641da0d2f9c9f34110d66a538e
pdf-font-stream PDF embedded font (sfnt) at offset 0xF210 5640 bytes
font_01_sfnt_off00010536.bin
ad09270b9a0e3e2edda20a71d6590dfc584cdcea93b9f0d993f2ba94814b3abd
pdf-font-stream PDF embedded font (sfnt) at offset 0x10536 11776 bytes