Malicious PDF — malware analysis report

Static analysis result for SHA-256 83e31b8a841b242b…

MALICIOUS

PDF

67.3 KB Created: 2021-09-27 00:53:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: f430a3ef4473090e750114406e76aa58 SHA-1: f9b7dedc5c1406c3ea1d245abad7c5c9f8922ead SHA-256: 83e31b8a841b242b82419a20fee22731b9fbf938433bfc96c4006348f76dd529
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs pointing to various domains, suggesting a link farm or redirection scheme. One heuristic indicates a 'disposable link farm' on disposable hosting, further supporting this. While no scripts were explicitly extracted, the PDF format itself can embed JavaScript, and the nature of the URLs suggests an attempt to direct users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

Heuristics 5

  • 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 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://airsoft1.ro/files/file/52883263032.pdf In PDF document text
    • http://limobebe.com/userfiles/files/furafoxokudutebonufeto.pdfIn PDF document text
    • http://eunlocker.com/Images/Editor/file/namimo.pdfIn PDF document text
    • http://pandoraecza.com/genelresimler/file/mefutifajas.pdfIn PDF document text
    • http://anael.fr/fckeditor/userfiles/file/zaperixuw.pdfIn PDF document text
    • http://nhatrangpalacehotel.com/app/webroot/upload/files/bekunebetipupakevisu.pdfIn PDF document text
    • https://satesayap.com/contents/files/nanovedew.pdfIn PDF document text
    • https://www.projectorrentals.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614c6df43ab1e---78939148316.pdfIn PDF document text
    • https://apartmani-mestrovic-krk.hr/files/52892941551.pdfIn PDF document text
    • https://bilalyapidekorasyon.com/userfiles/file/wawonevugutabus.pdfIn PDF document text
    • https://www.southdownscellars.co.uk/ckfinder/userfiles/files/timiwugizolir.pdfIn PDF document text
    • http://phrabat.net/UserFiles/File/dapodobepemekokevokexigex.pdfIn PDF document text
    • https://kaskad-74.ru/images/uploads/99562002086.pdfIn PDF document text
    • http://erdbau-rauch.at/29620676840.pdfIn PDF document text
    • http://thuexe7cho.vn/upload/files/jiluzaburopevuxuzuxivi.pdfIn PDF document text
    • https://www.baileysmilk.com/wp-content/plugins/super-forms/uploads/php/files/0932fcb70d1c12457b757ab071e454f4/jezel.pdfIn PDF document text
    • http://helder-effect.nl/userfiles/file/45174007498.pdfIn PDF document text
    • http://faradbox.pl/files/file/ronizilal.pdfIn PDF document text
    • http://nhuaduongnhapkhauaz.info/upload/files/50843385262.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/LPIa9PGmDLg/uplcv?utm_term=brain+app+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_off0000aaec.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAAEC 9996 bytes
SHA-256: a43cef56c883bfb30736d1cff5aac49038e8583f238717848bfbc756e9f4beed
font_01_sfnt_off0000c10b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC10B 15524 bytes
SHA-256: 12bf297e830b9d5c520beede6cc58684c7166cdfa61e580f35cda8d11d052d8b
font_02_sfnt_off0000e81d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE81D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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