Malicious PDF — malware analysis report

Static analysis result for SHA-256 21767ce443c2239b…

MALICIOUS

PDF

81.6 KB Created: 2021-09-03 04:05:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 7409d4c692a3d5d35e111dbd9a1a6ee1 SHA-1: 5104e0e0af98cf580a6f06b0f1143ea2f5352fcc SHA-256: 21767ce443c2239b897f820eab8be7096e724255e82a810ec02fdb0ef7b78a60
156 Risk Score

Malware Insights

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

This PDF file was flagged by multiple heuristics as malicious, including a critical ClamAV detection and an ML classifier. It contains numerous embedded URLs that point to compromised CMS uploads and disposable hosting, suggesting a link farm designed to redirect users to malicious sites. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, further obscuring its true intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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 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://synerhu.ru/uplcv?utm_term=sinusitis+pediatria+tratamiento+pdf PDF link annotation
    • https://dispomydeal.com/wp-content/plugins/super-forms/uploads/php/files/822f1a7c8c4fbfa7c2df986d00b07d19/57033149744.pdfIn PDF document text
    • https://christembassyromford.org/wp-content/plugins/super-forms/uploads/php/files/6f42d2c8b9badb1a220ad8c27fd4acc2/lukepekobadukezore.pdfIn PDF document text
    • http://zonazero.es/userfiles/file/22212158352.pdfIn PDF document text
    • https://groupunsur3.com/contents//files/79371228125.pdfIn PDF document text
    • http://guojingmall.com/userfiles/file///2327556504.pdfIn PDF document text
    • http://df-2.de/images/daten/file/bofobefupikeme.pdfIn PDF document text
    • https://arizonalightingsales.com/wp-content/plugins/super-forms/uploads/php/files/d71dd1bcdfa1d5098ffe42b834ef92da/tivis.pdfIn PDF document text
    • http://stadtbild-intervention.de/Quansis/ckfinder/userfiles/files/97721277822.pdfIn PDF document text
    • https://sygimportaciones.com/wp-content/plugins/super-forms/uploads/php/files/ocur1ucqnlff4vuvu0d7gpiumk/41349272378.pdfIn PDF document text
    • https://atputasbazes.lv/images/userfiles/files/lisiv.pdfIn PDF document text
    • https://purpleleafestatebuyers.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b784ca0fb86---10049724508.pdfIn PDF document text
    • https://teplitsyoptom.ru/wp-content/plugins/super-forms/uploads/php/files/28c39cb19ac07eb37bbfd2c527729f11/duziv.pdfIn PDF document text
    • http://www.ebsjosepirosamaria.com/wp-content/plugins/formcraft/file-upload/server/content/files/16097c61770938---27691303871.pdfIn PDF document text
    • https://loskutova.site/wp-content/plugins/super-forms/uploads/php/files/80f3e82e6f445498ad55c27156ba9384/loxawuxiwutuniba.pdfIn PDF document text
    • https://acethamessecurity.co.uk/wp-content/plugins/super-forms/uploads/php/files/b9f1c4192b366f37b36f5d78b6387d22/tolubekizared.pdfIn PDF document text
    • https://webmenuplus.com/images/file/70750258747.pdfIn PDF document text
    • http://yuanyoujie.vip/userfiles/file/38274860192.pdfIn PDF document text
    • https://swagath.co/new/ckfinder/userfiles/files/nisivonoriropeguwijumomi.pdfIn PDF document text
    • http://russkiivopros.com/images/FCKeditor/file/bobolagunozur.pdfIn PDF document text
    • http://www.belladermeestetica.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16074bc618f55b---bodixuxibubakedebasawagev.pdfIn PDF document text
    • https://shaplaconsulting.com/app/webroot/ckfinder/userfiles/files/49498877745.pdfIn PDF document text
    • http://iwish-cosmetics.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609fd9711d153---3909615391.pdfIn PDF document text
    • https://ip-pharma.net/data/files/68648808689.pdfIn PDF document text
    • https://asharfilalkulfi.com/ckfinder/userfiles/files/wixikitesirozipiw.pdfIn PDF document text
    • https://rt9.rspo.org/ckfinder/userfiles/files/sibovavegitixinorojusogak.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_off0000da51.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA51 17744 bytes
SHA-256: 3695ce56742de5c8df50fdd2d1dc6adaf16c11bc46dc5280b2aed6b4f2876405
font_01_sfnt_off000107c1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x107C1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011fd8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11FD8 10788 bytes
SHA-256: 07a4c46c5f232cb7d98363d6f89a5472a4d8cda694e241537465e516dacb38aa

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