Malicious PDF — malware analysis report

Static analysis result for SHA-256 c8458ca636f2da92…

MALICIOUS

PDF

81.2 KB Created: 2021-09-15 18:59:03 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 9523d9943431b6329696d4600b751cea SHA-1: 571cd7a6d4f824202757065046ff93cb3cace328 SHA-256: c8458ca636f2da9257eecfca378f2f61ecd98bf7dedc4953e61b20d63c25ee24
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which point to compromised CMS upload storage or disposable hosting, indicating a link farm designed to obscure the ultimate destination. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware distribution. While no scripts were directly extracted, the nature of the link farm and the presence of a 'download button' heuristic suggest the PDF is intended to lure users to click through to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://grandp.ru/userfiles/file/junamonaxime.pdf In PDF document text
    • http://dichvu12h.net/userfiles/file/zeweloxesofotun.pdfIn PDF document text
    • https://nazragame.com/calisma2/files/uploads/fonujatufixug.pdfIn PDF document text
    • https://jck.ro/userfiles/file/zitarebupepuve.pdfIn PDF document text
    • http://phdpecs.hu/userfiles/files/2153922324.pdfIn PDF document text
    • http://demenagements-remond.fr/userfiles/file/20210912113512.pdfIn PDF document text
    • https://confidence-ist.mktechsol.com/ckfinder/userfiles/files/56973638975.pdfIn PDF document text
    • https://premium-house.uz/images/file/manosunoxatefajo.pdfIn PDF document text
    • https://webmakler.org/userfiles/file/bejemefija.pdfIn PDF document text
    • http://thongthien.vn/upload/files/kakesepotunewusuxap.pdfIn PDF document text
    • http://www.farmaciapenil.es/userfiles/files/23601949425.pdfIn PDF document text
    • http://rsti.biz/files/fck/file/pukedoxegikefakup.pdfIn PDF document text
    • http://caacoding.net/wp-content/plugins/formcraft/file-upload/server/content/files/161303e8051a47---66510306367.pdfIn PDF document text
    • http://www.cascinasorigherio.it/wp-content/plugins/formcraft/file-upload/server/content/files/161321b3fdbee6---13760203984.pdfIn PDF document text
    • http://www.introspekta.si/ckfinder/ckeditor_uploaded_files/files/95337410469.pdfIn PDF document text
    • http://giasuthienphuc.com/Images_upload/files/fegagilenawekez.pdfIn PDF document text
    • https://traiteur-troyes-mariage-buffet-aube-10.blaisot-traiteur.fr/ckfinder/userfiles/files/buzalaja.pdfIn PDF document text
    • http://www.icodar.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e235b2adb4---wunadoren.pdfIn PDF document text
    • https://toolsatool.com/userfiles/files/13668055839.pdfIn PDF document text
    • https://condominiovillage.com/userfiles/file/rupab.pdfIn PDF document text
    • https://ciela13.leaddeehub.com/userfiles/files/76571218855.pdfIn PDF document text
    • https://vetregistr.com/ckfinder/userfiles/files/62361161701.pdfIn PDF document text
    • http://yh-nutri.com/filespath/files/20210912081103.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/DOqCt-cVA4I/uplcv?utm_term=mp4+song+download+sitePDF 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_off0000d61f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD61F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ee31.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE31 18708 bytes
SHA-256: 9785b775daf7aaa1fc53f5b7a8514c7b8eb554f0d1d86e633c7e74952b8f2de9
font_02_sfnt_off00011efa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11EFA 10624 bytes
SHA-256: 707a0d7b519c0fc9e3c5bd11d224a40b3b87e9383578c4965cd92cdc7156d8dc

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