Malicious PDF — malware analysis report

Static analysis result for SHA-256 81cd7542ee1a43f5…

MALICIOUS

PDF

76.8 KB Created: 2021-03-31 22:04:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: d1f56ab41630254dfe4e934bc9f7b43f SHA-1: 755107892362a3b620bd849b43b6436da65f36d5 SHA-256: 81cd7542ee1a43f5ed1a33f74a6dc30b802b4be3e61324c17e79f23775d03999
186 Risk Score

Malware Insights

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

The PDF file, identified as malicious by ClamAV and an ML classifier, contains a large number of external links, suggesting a link farm or SEO manipulation tactic. One of the embedded URLs, 'https://zajinet.ru/strik?utm_term=pavel+tsatsouline+training+program+pdf', is particularly suspicious. While no scripts were directly extracted, the PDF structure and the presence of numerous external links indicate a potential for distributing malicious content or redirecting users to phishing sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • 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
  • 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://zajinet.ru/strik?utm_term=pavel+tsatsouline+training+program+pdf
    • https://static.s123-cdn-static.com/uploads/4445880/normal_5fdf0310e0dd3.pdf
    • https://cdn-cms.f-static.net/uploads/4495413/normal_60561c9352df9.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://s3.amazonaws.com/kufazete/76348855765.pdf
    • http://zuferujej.epizy.com/35669164417.pdf
    • http://zumewozuzetarun.epizy.com/dorothy_dinosaur_cake_template.pdf
    • https://107a3552-ed21-4f5d-95e3-510b6eae4444.filesusr.com/ugd/21bbef_56547f44a615457a9db4dfa1c29e2c0c.pdf?index=true
    • https://810dce77-56ab-4324-823a-3549757f4eab.filesusr.com/ugd/1fad07_fe0cf6d9736147399d4d9d60994299ac.pdf?index=true
    • https://089130c0-62ae-4bf1-a93c-656440fe8451.filesusr.com/ugd/738632_5f1b1832317845e589bad7171fdc040b.pdf?index=true
    • https://s3.amazonaws.com/remavuj/mogirotokonoraduj.pdf
    • https://d8acad56-eb9a-42d1-a06c-a695c5b02328.filesusr.com/ugd/0ad6c7_1080b92b0c774a77bb96e5107bba8134.pdf?index=true
    • https://77bc4ea4-de20-41c0-a463-a5315db628d9.filesusr.com/ugd/2c69e3_95f8ef4081584c83ab3870b16eb7b969.pdf?index=true
    • http://valapapiwusujeg.rf.gd/download_film_rudy_habibie_1_lk21.pdf
    • http://tuninedup.epizy.com/clonapp_messenger_mod_apk_2019.pdf
    • https://2acf176d-1645-44e4-83be-c67f7ac9af6b.filesusr.com/ugd/e72dd6_6a9f058c95db4286af92e30f608b076b.pdf?index=true
    • https://b64dd490-e5b9-492f-89ff-e398ecee904c.filesusr.com/ugd/5926b4_8ff1bf9ef86644d2b887f08a0304c0c2.pdf?index=true
    • http://suwugiborewetel.rf.gd/sociology_class_12_project.pdf
    • https://s3.amazonaws.com/takateg/mokoxadewumilazemarim.pdf
    • http://wonetone.rf.gd/pkp_bielsko_biaa_informacja_telefoniczna.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_off0000eef6.bin
45ec2eb2d57193de8c8a917fa7af7d200a25624ef295659dcdf8b61316a2b854		 pdf-font-stream PDF embedded font (sfnt) at offset 0xEEF6 5424 bytes
font_01_sfnt_off0001015c.bin
ae2e038015ba31619fefc94ab08404b53938229ca76ff5e2b295f7b21ca31aee		 pdf-font-stream PDF embedded font (sfnt) at offset 0x1015C 10532 bytes

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