Malicious PDF — malware analysis report

Static analysis result for SHA-256 813e3b7f35801432…

MALICIOUS

PDF

86.7 KB Created: 2021-09-21 07:55:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 20e1330e0abac645b8e352d4768bac16 SHA-1: e58617ad4112c3e78065af526e951175b3649869 SHA-256: 813e3b7f358014324ab38365b86903144b67b43541c9e0f85a1a905838660473
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample contains embedded JavaScript, a common technique for executing malicious code within PDFs. It also features a link farm pointing to multiple distinct hosts, many of which are hosted on disposable domains or compromised WordPress sites, suggesting an attempt to obscure the final destination or leverage compromised infrastructure. The ClamAV detection and ML classifier strongly indicate malicious intent, likely for phishing or malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

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 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://hfbee.tw/upload/ckfinder_temp/files/20210912043639.pdf In PDF document text
    • http://worshipedia.net/sites/default/files/file/91352469430.pdfIn PDF document text
    • http://fantalife.nl/userfiles/file/57553299594.pdfIn PDF document text
    • https://ip-kamera-rendszer.hu/ckfinder/userfiles/files/81659796084.pdfIn PDF document text
    • http://traiteur-ribot.fr/userfiles/file/27872463977.pdfIn PDF document text
    • http://camonetinternational.com/files/file/lotitoxu.pdfIn PDF document text
    • https://valeaflorilor.ro/img/uploads/file/dudatagawenidomew.pdfIn PDF document text
    • https://precisionautoandac.com/wp-content/plugins/super-forms/uploads/php/files/d503f1c8bea816d14b145d6056084b37/36656267237.pdfIn PDF document text
    • https://www.golaw.net/wp-content/plugins/formcraft/file-upload/server/content/files/1614404f56d561---41103759422.pdfIn PDF document text
    • http://studioingegneramato.com/userfiles/files/godikobesoriv.pdfIn PDF document text
    • http://eraldocomo.it/userfiles/files/vikopir.pdfIn PDF document text
    • http://torremaggiore.sitmap.it/files/files/mubuf.pdfIn PDF document text
    • https://steammining.com/userfiles/file/81542675110.pdfIn PDF document text
    • http://libron.pl/fckupload/assets/file/nujorozajebiraxotat.pdfIn PDF document text
    • http://chronocertif.com/userfiles/file/zozuzosazijabimaz.pdfIn PDF document text
    • https://cartolmania.it/file/58559207575.pdfIn PDF document text
    • http://kronospan-mofa.hu/editor_up/35600180291.pdfIn PDF document text
    • http://daejonggyoyc.com/userfiles/file/20210909130623.pdfIn PDF document text
    • http://salocchi.it/userfiles/files/vevaf.pdfIn PDF document text
    • http://klasykarozrywki.pl/public/images/fck/file/17469474652.pdfIn PDF document text
    • http://agriturismolionsfarm.it/userfiles/files/zaxisemujimepujalitu.pdfIn PDF document text
    • https://snpwachq.com/files/js/ckfinder/userfiles/files/16784547581.pdfIn PDF document text
    • http://www.mondzorgvesa-voorschoten.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16135ffe73df8c---10298500102.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/cv9VXjIrmdE/uplcv?utm_term=intellivision+emulator+androidPDF 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_off0000ef22.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF22 17548 bytes
SHA-256: 5efb137d2f956a176a5b36646aa9da4d9c06774e6eba91c020db2ec43f198069
font_01_sfnt_off00011cd4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11CD4 10528 bytes
SHA-256: f464f067161b9d26b8c9ef0d71399d29b9f06afbcc99d02a13c7a3253fb80dfb
font_02_sfnt_off000134d0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x134D0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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