Malicious PDF — malware analysis report

Static analysis result for SHA-256 b31e8112330c9093…

MALICIOUS

PDF

84.6 KB Created: 2021-09-13 21:27:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: c51cc419f4785639f1f325d0f379274a SHA-1: c4a9e51dad09b97010639bc2520223f41e1dc20f SHA-256: b31e8112330c9093f262c6d34ee81a7f36f0c2f8472589a5fde11616b1894b87
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous embedded URLs pointing to potentially malicious or unknown domains. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for human readability but rather to host these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

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://cesvil.it/filesUploads/file/44571729846.pdf In PDF document text
    • http://opusincertum.it/userfiles/files/xazexigin.pdfIn PDF document text
    • http://oiseau-bleu-morzine.com/userfiles/file/57914692932.pdfIn PDF document text
    • http://skontrolsengineering.com/file_media/file_image/file/8390023330.pdfIn PDF document text
    • http://circuitvietnamcambodge.com/hinhanh/file/79397122184.pdfIn PDF document text
    • http://uralteplostroy.ru/content/file/4415343977.pdfIn PDF document text
    • http://saluteebenesseresas.it/userfiles/files/77503119719.pdfIn PDF document text
    • http://sjanzee.nl/file/muzepilazem.pdfIn PDF document text
    • http://www.alfapilates.pl/upload/file/71408123211.pdfIn PDF document text
    • https://stalbeckers.nl/userfiles/image/file/pepomuvutuw.pdfIn PDF document text
    • https://excore.hu/ckfinder/userfiles/files/55577469734.pdfIn PDF document text
    • https://ipssecurityconsultants.com/ckfinder/userfiles/files/diwanifox.pdfIn PDF document text
    • http://xn--80aaeiengkwpz6p.xn--p1ai/pub/file/gitusij.pdfIn PDF document text
    • https://www.pferde-fuer-unsere-kinder.de/wp-content/plugins/formcraft/file-upload/server/content/files/161394f2027786---fotinigabased.pdfIn PDF document text
    • http://tiga.co.th/ckfinder/userfiles/files/43340283998.pdfIn PDF document text
    • http://sabaispa.net/userfiles/file/bofisejifunifigazumulaw.pdfIn PDF document text
    • http://christopherdallo.com/file/sanowekusotufet.pdfIn PDF document text
    • http://dakov.hu/_user/file/dogevemagometawatunir.pdfIn PDF document text
    • http://taemyung.com/data/upload/file/61964356835.pdfIn PDF document text
    • http://hamishehbaharcarpet.com/My_Project/Hamishe_bahar/ahar_img/files/24326042410.pdfIn PDF document text
    • http://elfast.ru/userfiles/file/judununokujelateg.pdfIn PDF document text
    • http://purepassion.pl/userfiles/file/89432292162.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/DOqCt-cVA4I/uplcv?utm_term=canli+tv+indir+bedavaPDF 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_off0000e972.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE972 17836 bytes
SHA-256: 91772f43637256374dc491ff40932f91db21590d3ede70ccdda23bf40c311537
font_01_sfnt_off000115f7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x115F7 10188 bytes
SHA-256: 61673844229238a4768a2a5eb6bb8588a7e0a30d10ffd31bf34f94a957237eee
font_02_sfnt_off00012ced.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12CED 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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