Malicious PDF — malware analysis report

Static analysis result for SHA-256 b91cdf00d8841b18…

MALICIOUS

PDF

87.8 KB Created: 2021-10-10 14:00:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-02
MD5: 645ece0f3e4fa51b20fc0af19a0dd52c SHA-1: e30f1f72e567e31ecf2f13cabf7c889b9402da0c SHA-256: b91cdf00d8841b1841d10eaac7b6ed8c7b372d36d2f40c68a45c6eb0d0767c65
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous embedded URLs, many of which point to disposable hosting, suggesting a link farm or phishing lure. The PDF structure and heuristic firings strongly suggest it is designed to redirect users to external, potentially malicious, sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://www.oe.com.tw/ezadmin/ckfinder/userfiles/files/bebuxoweno.pdf In PDF document text
    • https://zhongzing.com/uploads/files/202110031409486066.pdfIn PDF document text
    • https://gruntbudowa.pl/files/file/65770339162.pdfIn PDF document text
    • https://nolimitscenter.be/peausitive/images/FCKeditor/file/xuveboduwatejurifukawisif.pdfIn PDF document text
    • http://anninh247.info/upload/files/rozivasun.pdfIn PDF document text
    • http://yenidenyuzlendirme.com/ckfinder/userfiles/files/29492594085.pdfIn PDF document text
    • http://123flower.doweb.kr/upload/files/jutavinusobom.pdfIn PDF document text
    • http://chikatere.com/Upload/files/limopewi.pdfIn PDF document text
    • http://www.look4job.gr/images/_user_na/file/56303669833.pdfIn PDF document text
    • http://imobilestore.de/userfiles/file/suloleliri.pdfIn PDF document text
    • https://alternatifhirdavat.com/upload/ckfinder/files/dageduniponatixaregizat.pdfIn PDF document text
    • https://g-ortho.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1615025814cd77---90039896093.pdfIn PDF document text
    • https://www.truckersplantparts.co.uk/ckfinder/userfiles/files/67924835154.pdfIn PDF document text
    • http://qcfloor.com/userfiles/file/liwenifijax.pdfIn PDF document text
    • http://www.ambatownship.com/ckfinder/userfiles/files/56180872930.pdfIn PDF document text
    • https://dobre-akce.cz/media/files/file/40421956648.pdfIn PDF document text
    • https://magyar-logyogyasz.hu/fileok/file/mefakavuvozakabolu.pdfIn PDF document text
    • https://orrizon.ru/images/file/6026656112.pdfIn PDF document text
    • http://banghetretruc.com/media/ftp/file/gatigopekovawaj.pdfIn PDF document text
    • https://10fci.net/userfiles/file/zimavufaxawomodoj.pdfIn PDF document text
    • http://murito.fr/ckfinder/userfiles/files/negatitadexatumizatede.pdfIn PDF document text
    • https://underworldgear.com/admin/images/fckImg/file/29159509102.pdfIn PDF document text
    • https://homestayhoian.vn/uploads/image/files/guvifolotukag.pdfIn PDF document text
    • https://inclinedigital.com/wp-content/plugins/formcraft/file-upload/server/content/files/161582e93e2406---70996378859.pdfIn PDF document text
    • https://ifbscalidad.eus/files/galeria/files/51493435373.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/ngfLrbzwjls/uplcv?utm_term=in+a+cubic+close+packed+structure+of+mixed+oxides+the+lattice+is+made+up+ofPDF 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_off0000ea53.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA53 19724 bytes
SHA-256: 5c0063aa909b761805ed786ba7f6d537ce2646f52ea7a7881356635732697da2
font_01_sfnt_off00011e35.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E35 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001364c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1364C 11272 bytes
SHA-256: 1b6003752c1a6f042f571bc347baa58a122d95176c8e4115a94fe81851812f7b