Malicious PDF — malware analysis report

Static analysis result for SHA-256 5357637eb630c81e…

MALICIOUS

PDF

74.2 KB Created: 2021-09-20 05:05:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 6bcb79c55e7d585f3b33e01167aa26af SHA-1: e0bd8a4cde432cd1e8fa12f7032aab917a76dc30 SHA-256: 5357637eb630c81e35461715448d95e47a4bdf92f92b9bebbfee2be8809cc8bd
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous external links, with a high-severity heuristic flagging it as a link farm on disposable hosting. One link points to a URL that is algorithmically generated, suggesting malicious intent. The ClamAV detection and ML classifier further support its malicious nature, indicating it's likely used for phishing or distributing further malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://allytemp.ru/uplcv?utm_term=standard+form+of+the+quadratic+function PDF link annotation
    • http://marasintl.com/public/ckfinderuploads/files/ritinavawalavofiveregi.pdfIn PDF document text
    • https://prosaison.fr/userfiles/files/16474432534.pdfIn PDF document text
    • https://homeuu.biz/upload/ckeditor/pages/files/sasimaki.pdfIn PDF document text
    • http://apartament-krokus.pl/userfiles/file/sifopegigadisexenev.pdfIn PDF document text
    • https://arch.ua/ckfinder/userfiles/files/95490998175.pdfIn PDF document text
    • http://ecole.ru/text/images/file/40280782003.pdfIn PDF document text
    • http://innotack.com/userfiles/files/66674948381.pdfIn PDF document text
    • http://thomasgearon.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/jisediko.pdfIn PDF document text
    • http://nd-58.ru/wp-content/plugins/super-forms/uploads/php/files/2965dc9be754c4e7d5309c9e5a924f0d/40170336110.pdfIn PDF document text
    • https://macleanpinesdrivingschool.com.au/wp-content/plugins/super-forms/uploads/php/files/bc152321a1355d7911e52daaa0a925f7/33255939617.pdfIn PDF document text
    • https://grandiosieventinuziali.it/filesUploads/file/29940930086.pdfIn PDF document text
    • http://okeefesreef.com/ckfinder/userfiles/files/81383266556.pdfIn PDF document text
    • http://avandcie-automation.fr/ckfinder/userfiles/files/73601688840.pdfIn PDF document text
    • http://jshanwoo.com/ckfinder/userfiles/files/jogisadekivifidexejewobiw.pdfIn PDF document text
    • https://alwaysthesame.pt/site/upload/file/21456730982.pdfIn PDF document text
    • http://consoles-a-gagner.com/fckeditor/userfiles/file/77660283426.pdfIn PDF document text
    • https://netron.pt/app/webroot/media/files/52425042861.pdfIn PDF document text
    • http://viettranslators.com/webroot/img/files/74487897449.pdfIn PDF document text
    • https://nslogisticservice.com/userfiles/files/xuwipotamor.pdfIn PDF document text
    • http://soft-pro.hr/upload/datoteke/83688712291.pdfIn PDF document text
    • http://www.loockuniformes.com.br/home/wp-content/plugins/formcraft/file-upload/server/content/files/1613837db11508---pefabubobopurixapizireb.pdfIn PDF document text
    • https://stthomasorthodoxchurchsouthpampady.com/userfiles/file/35633771462.pdfIn PDF document text
    • http://vekosgroup.ru/userfiles/file/dugibexetusaperet.pdfIn 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://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_off0000bf34.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBF34 10848 bytes
SHA-256: f775e16a01af0d76668b839015158cf41a13d1f094b17da59415fac967b808f5
font_01_sfnt_off0000d7d2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD7D2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000efe4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFE4 16836 bytes
SHA-256: f0893d8da57cc0d72c29161174f76d509e015f3b27eb098dc47c1972ff443499