Malicious PDF — malware analysis report

Static analysis result for SHA-256 b31dcb87a2ea56ca…

MALICIOUS

PDF

86.0 KB Created: 2021-09-10 01:22:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 3f0f54b0dc48efcfdc2dea37d24f7079 SHA-1: 553a735962121648199a25805b06fde2f307dc8a SHA-256: b31dcb87a2ea56cacc42d978c77243188a58094c1f9f42abf45a52366a84ab98
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ML classifiers and ClamAV as malicious. It contains numerous embedded URLs, with one specifically identified as a link farm hosting multiple PDF files. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a pattern of using disposable hosting for these linked files, suggesting a phishing or malware distribution scheme. No scripts were extracted, but the overall structure points to a malicious document designed to redirect users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

Heuristics 5

  • 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 http://bualuang101.com/backoffice/upload/files/lulosabajaju.pdf In PDF document text
    • http://xinyuemu.net/assets/202109/files/20210903053807980625.pdfIn PDF document text
    • http://hanifeugur.com/image/files/pexikoralopakudiwame.pdfIn PDF document text
    • http://enjoy.sk/editor_uploads/system/files/wisulomerarigode.pdfIn PDF document text
    • https://cultureresortpokhara.com/assets/userfiles/files/kufobedulab.pdfIn PDF document text
    • https://catwalkdogcome.com/editor_upload_image/file/zemoburefut.pdfIn PDF document text
    • https://www.drmarlenebothma.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/161365535162ac---16889051390.pdfIn PDF document text
    • https://zivotzaokny.eu/res/file/38378181688.pdfIn PDF document text
    • https://navoloki.mebel18.com/uploads/files/50307944296.pdfIn PDF document text
    • http://chongthamnguoc.vn/img/files/38465767372.pdfIn PDF document text
    • https://bodykneadstherapy.com.au/ckfinder/userfiles/files/fopaposavafob.pdfIn PDF document text
    • https://vibanghanoi.com/uploads/files/24578368918.pdfIn PDF document text
    • http://exima.kr/userData/board/file/32196495737.pdfIn PDF document text
    • http://auburn-companies.com/userfiles/files/bipazipabeteget.pdfIn PDF document text
    • http://lesmashclub.com/imgUpload/files/sarinonoruweririlago.pdfIn PDF document text
    • https://emartdeko.pl/galeria/file/68552714592.pdfIn PDF document text
    • http://aloisiquadri.it/userfiles/files/91078741688.pdfIn PDF document text
    • http://younewstoday.com/task/userimages/file/xiwezovazivunavevojoresam.pdfIn PDF document text
    • https://pavillonwohlen.ch/userfiles/files/gitulobifijovudugokekos.pdfIn PDF document text
    • https://www.ijmsir.com/ckfinder/userfiles/files/68728135462.pdfIn PDF document text
    • http://www.gitialiganjlko.org/ckfinder/userfiles/files/dokevasukebaxi.pdfIn PDF document text
    • http://tangiahoang.com/skinkorea/Images_upload/files/bepekubumela.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/DOqCt-cVA4I/uplcv?utm_term=endless+run+magic+stone+2+game+download+for+androidPDF link annotation
    • 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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e8b4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE8B4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000100c6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x100C6 18080 bytes
SHA-256: 5ee1678a6ac04403e2d044d634735c977c085c8173c98e5315154ed8b66016cd
font_02_sfnt_off00013042.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13042 11108 bytes
SHA-256: 15878bd1eb37e2572aa60ac10493660b277a87a0111ad9fad9cad3a92245f9d2

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