Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef623cc67d44f1f0…

MALICIOUS

PDF

70.3 KB Created: 2021-09-27 13:58:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: b8c112d9bd10e41c66b6410f2ee2d6ae SHA-1: 5f1321ca549e0f0e6a14a947c4a4711d1ea17d13 SHA-256: ef623cc67d44f1f0724683e50a3818b6ff398096b0397722cd8eed86cdff745f
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was detected as malicious by ClamAV and an ML classifier. It contains numerous links to external URLs, many of which point to compromised WordPress sites or disposable hosting, suggesting a link farm designed to distribute further malware. The presence of PDF_RANDOM_URL_LINK and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics indicates a pattern of hosting malicious content on potentially compromised infrastructure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 7

  • 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.
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://queure.ru/uplcv?utm_term=best+multiplayer+io+games PDF link annotation
    • http://rw-hse-businessconsulting.de/userfiles/file/zamivutakovapa.pdfIn PDF document text
    • http://papianiarch.it/userfiles/files/balumitudata.pdfIn PDF document text
    • http://www.ambatownship.com/ckfinder/userfiles/files/mizabibe.pdfIn PDF document text
    • https://duext.com/wp-content/plugins/super-forms/uploads/php/files/7a2e96722c61e3e0050d711c1f608841/suvasenefaledol.pdfIn PDF document text
    • https://stpetejazz.com/wp-content/plugins/super-forms/uploads/php/files/4g9p94l1nhq9sd3mg8fcooav0q/xemere.pdfIn PDF document text
    • http://aaexpansionjoint.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614b6f1e36a3a---navuvififikolodisoz.pdfIn PDF document text
    • https://plasy.com/uploads/file/pejikenirexosegijuz.pdfIn PDF document text
    • https://thebottombillion.org/business_school/uploads/file/wafojapuzuzir.pdfIn PDF document text
    • http://ambulatorioveterinariopisillibertozzi.eu/userfiles/files/rekufejokedotiditaximimu.pdfIn PDF document text
    • https://alternativecarrepair.com/userfiles/file/87754083230.pdfIn PDF document text
    • http://improntediteatro.it/userfiles/files/81192430405.pdfIn PDF document text
    • http://guojingmall.com/userfiles/file///65131571941.pdfIn PDF document text
    • http://stressmanagement-karriere.de/userfiles/file/rumunu.pdfIn PDF document text
    • https://mymovingestimate.com/wp-content/plugins/super-forms/uploads/php/files/e19f09c92e2852f107901b4d97b5fa44/xawusufivina.pdfIn PDF document text
    • https://kheops-so.fr/ckfinder/userfiles/files/94885096361.pdfIn PDF document text
    • https://mangonebike.com/uploads/file/bekanusatinul.pdfIn PDF document text
    • http://aven.su/userfiles/file/topujatujataxomorexidabo.pdfIn PDF document text
    • http://chi-kara.net/Upload/files/rofanuxipadejawetonufuda.pdfIn PDF document text
    • https://nezrenweb.com/calisma2/files/uploads/4307295830.pdfIn PDF document text
    • http://amunt.madteam.net/ckfinder/userfiles/files/wijigoxe.pdfIn PDF document text
    • http://magogaralbamoble.com/galeria/files/68433077337.pdfIn PDF document text
    • http://nwatchonline.org/userfiles/file/bawuxirejuranapezesifesig.pdfIn PDF document text
    • http://www.medicellbank.com/userfiles/files/29671335710.pdfIn PDF document text
    • http://architettotoma.it/userfiles/files/pileremopibav.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_off0000b2bb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB2BB 10760 bytes
SHA-256: 8e7d58725259d73189bfe6cee0ec543c3a347eb57cd1cb977b0f474b9fd0b29c
font_01_sfnt_off0000cb91.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB91 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e3a3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE3A3 15820 bytes
SHA-256: c4448d0c5524eb388de962567ed62a0b49b672adc2016380b51883910926cebe

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