Malicious PDF — malware analysis report

Static analysis result for SHA-256 3f91f2680bdd911a…

MALICIOUS

PDF

75.1 KB Created: 2021-03-04 05:57:19 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-17
MD5: 1e7b2814c63cd9849ecf04f7bd6c645b SHA-1: 1625340efc5ac894ebcbf2ac870b109b5f2cd431 SHA-256: 3f91f2680bdd911af9e1239230056273df0189c571036732dd56c59fd3bc41da
226 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution T1059.007 JavaScript

This PDF file is identified as malicious by ML classifiers and ClamAV, and exhibits characteristics of a link farm designed to host numerous external PDF files. The document body, though obfuscated, suggests a lure related to 'functions precalculus worksheet', likely intended to trick users into downloading further malicious content. The presence of multiple external URLs and the 'remote-support tool lure' heuristic indicate an attempt to exploit user trust for malicious purposes, potentially leading to the execution of further payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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.
  • Remote-support tool lure high SE_REMOTE_SUPPORT_LURE
    Document instructs the user to install, open, or connect with a remote-support tool such as AnyDesk, TeamViewer, Quick Assist, or ScreenConnect — high-risk in an unsolicited document
  • 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://xajibur.ru/wix?keyword=functions+precalculus+worksheet PDF link annotation
    • http://discovljzg.fun/7255531450460z6l.pdfIn PDF document text
    • https://xorigikaku.weebly.com/uploads/1/3/1/1/131164164/67d58662f855c.pdfIn PDF document text
    • https://fusajebotiv.weebly.com/uploads/1/3/4/3/134320253/8513715.pdfIn PDF document text
    • https://cdn.sqhk.co/vawadawuleja/eiaghjb/xikeforeregup.pdfIn PDF document text
    • https://cdn.sqhk.co/migukosodaza/gfWgiij/swath_definition_synonyms.pdfIn PDF document text
    • https://malosana.weebly.com/uploads/1/3/5/3/135323031/9264165.pdfIn PDF document text
    • https://jifosibupegexuv.weebly.com/uploads/1/3/4/6/134692258/xurinekemirudu.pdfIn PDF document text
    • https://popetufuwude.weebly.com/uploads/1/3/1/4/131483025/sapavi.pdfIn PDF document text
    • https://nivosuvadifo.weebly.com/uploads/1/3/5/3/135384950/limenek-mufitilikotul-novavibalidugo.pdfIn PDF document text
    • http://pokemonrivals.online/kolasenijapimepipofawixczi9.pdfIn PDF document text
    • https://cdn.sqhk.co/baxorurifina/ehjOgie/geradotixamasonazipasa.pdfIn PDF document text
    • https://nasamokazefo.weebly.com/uploads/1/3/6/0/136049887/texofowinubujo_kuzifomigoraku_tasubasekabeko.pdfIn PDF document text
    • https://nuvisinuxaxo.weebly.com/uploads/1/3/1/3/131383681/winitiniwivajiko.pdfIn PDF document text
    • http://fb-copyright-help-from.com/susuwekinugovuhfdfm.pdfIn PDF document text
    • https://zikepasut.weebly.com/uploads/1/3/4/1/134108801/lurakovefijobas_jafukoxaxujevul.pdfIn PDF document text
    • https://cdn.sqhk.co/nipigagavadu/jcijjiw/teamviewer_for_remote_control_pc.pdfIn PDF document text
    • http://test123test.xyz/the_hobbit_part_3_movie_download_in_hindijsw2y.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_off0000ebe5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEBE5 5132 bytes
SHA-256: 81df98b2f4b87f940f164e4d6fd90901ce0635069764aedf855d05df9d674bb9
font_01_sfnt_off0000fd6b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD6B 10072 bytes
SHA-256: 8365fc382dc44242f4f6c07979435b0901ea633610f8e84ef9f168fd17eff37f

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