Malicious PDF — malware analysis report

Static analysis result for SHA-256 37ff87ba8e73336e…

MALICIOUS

PDF

71.2 KB Created: 2021-09-04 18:36:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 1391c363e70d8ae5f63d2ec6b5a64181 SHA-1: 84d963fb90e8bdeae7c2f0a3077bfb0bc6d2e971 SHA-256: 37ff87ba8e73336e35c1bfcc509e6733767595fd461b795dfa1c61d1de6a4506
156 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics as a link farm, with many URLs pointing to potentially compromised or disposable hosting. The ML classifier and ClamAV also identified it as malicious, specifically a phishing trojan. The embedded URLs suggest an attempt to redirect users to malicious sites, likely for credential harvesting or further malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9916

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 http://koryosushi.com/uploads/files/mulobujopulegulas.pdf In PDF document text
    • http://infunplastic.com/d/files/vureropenateron.pdfIn PDF document text
    • http://aj-logistics.com/stock/userfiles/file/ronuta.pdfIn PDF document text
    • https://holzhaus-suedtirol.it/wp-content/plugins/formcraft/file-upload/server/content/files/1606cb069c9052---tewopudupo.pdfIn PDF document text
    • http://challendor.com/fckeditor/upload/file/zebawuxefiz.pdfIn PDF document text
    • http://optimus.org.au/wp-content/plugins/formcraft/file-upload/server/content/files/1609f5b90e9f27---jitofadinobet.pdfIn PDF document text
    • https://www.domaine-vrignaud.com/ckfinder/userfiles/files/jadurepuwefakiresosa.pdfIn PDF document text
    • http://gesundimjob.at/images/content/files/48840356532.pdfIn PDF document text
    • http://rusiuojigalvoji.lt/wp-content/plugins/formcraft/file-upload/server/content/files/160ec4b76a24cc---14943704905.pdfIn PDF document text
    • https://bluetact.com/ckfinder/userfiles/files/koruzozivino.pdfIn PDF document text
    • https://www.hediyevideo.com/wp-content/plugins/formcraft/file-upload/server/content/files/160847b4858803---fevepukutupujobiv.pdfIn PDF document text
    • http://vmkmsz.hu/userfiles/file/roxuzusapigikejal.pdfIn PDF document text
    • http://sskj.pl/userfiles/file/jotusanetodudam.pdfIn PDF document text
    • http://dh-cell.com/ckfinder/userfiles/files/butimezufemazozi.pdfIn PDF document text
    • https://www.artikel238.nl/emmwebbit/resources/ckfinder/userfiles/files/11951802022.pdfIn PDF document text
    • http://dh-cell.com/ckfinder/userfiles/files/pegomilolekirapomopene.pdfIn PDF document text
    • https://nanyangtextile.com/userfiles/file/futugurupo.pdfIn PDF document text
    • https://evrenmentese.com/upload/ckfinder/files/nuledexokikolepuxedidabuv.pdfIn PDF document text
    • https://anjingliar2.com/contents//files/62424099798.pdfIn PDF document text
    • http://lifestyleufa.ru/wp-content/plugins/super-forms/uploads/php/files/db61bf490fa05984128504a4adaf7d50/32768116071.pdfIn PDF document text
    • http://hndgyl.com/v15/Upload/file/20218211351334812.pdfIn PDF document text
    • https://www.davinci.dk/wp-content/plugins/formcraft/file-upload/server/content/files/160d41227634aa---50537695422.pdfIn PDF document text
    • http://unipell.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160a1de2a0d463---15487142206.pdfIn PDF document text
    • https://betentour.com/sites/default/files/file/13508344250.pdfIn PDF document text
    • http://asalsold.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608b421e094e9---91372145295.pdfIn PDF document text
    • http://nazycakes.com/userfiles/file/85525800911.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BkSY9tpko7c/uplcv?utm_term=dna+replication+video+worksheetPDF 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_off0000b734.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB734 10856 bytes
SHA-256: dd7e1b1eb3a5e3aa9c2563b7fdc7c25ed26362f551d58c6dbd4a70b239d58a4b
font_01_sfnt_off0000d045.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD045 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e857.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE857 14684 bytes
SHA-256: 03eb4865cd48c2f1acaa5402adad03637f740d051eb4bc8aecc0088733618f52

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