Malicious PDF — malware analysis report

Static analysis result for SHA-256 a77b2fb103580f80…

MALICIOUS

PDF

79.1 KB Created: 2021-09-10 07:59:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 50e1a06dbf6d2a557b03c0c96a89e00c SHA-1: e8be902c129ffbbe0bb609bedc16b1f8c901fe29 SHA-256: a77b2fb103580f80ef67ecf0b6b6c7a4dc3c33f9f6c1dfa2709103c3333d4fc0
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous URLs pointing to disposable hosting or compromised CMS upload directories. While no scripts were directly extracted, the PDF structure and link farm behavior suggest an attempt to lure users to external sites, likely for credential harvesting or further malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9968

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://doudou.tw/userfiles/files/buwukevuzabejinew.pdf In PDF document text
    • https://dorfadvertising.com/ckfinder/userfiles/files/91748452481.pdfIn PDF document text
    • https://radekslodkiewicz.pl/files/file/nomuladilotoberodo.pdfIn PDF document text
    • https://ijmscr.com/ckfinder/userfiles/files/xowane.pdfIn PDF document text
    • https://www.sophrologue-nimes.fr/upload/news/files/zanex.pdfIn PDF document text
    • http://drinkandshrink.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1612ed1a9c6d84---87785328394.pdfIn PDF document text
    • https://bcm.es/files/galeria/files/22880744832.pdfIn PDF document text
    • http://beautybybelief.com/admin/images/file/95838425549.pdfIn PDF document text
    • https://yourownadviser.com/ckfinder/userfiles/files/ludaxuwiberugutovo.pdfIn PDF document text
    • http://autoscuolecasetta.it/userfiles/files/joneluxarupamazip.pdfIn PDF document text
    • http://drukarnia-skawina.pl/app/webroot/media/files/gafajuguja.pdfIn PDF document text
    • http://yanartextil.com/firma/files/74333834728.pdfIn PDF document text
    • http://studiotecnicobonoli.com/userfiles/files/tizizi.pdfIn PDF document text
    • http://xn--80aafmoni2biho.xn--p1ai/admin/ckfinder/userfiles/files/natajirap.pdfIn PDF document text
    • http://sibmaxi.ru/userfiles/file/29665237906.pdfIn PDF document text
    • http://freewest.at/gubenix.pdfIn PDF document text
    • https://www.rougeindigo.com/ckfinder/userfiles/files/tujiriradaxibikobowivufi.pdfIn PDF document text
    • https://bosgo.mn/uploads/files/zidizukodurofezagilukup.pdfIn PDF document text
    • http://www.kliningstroy.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16136842769584---95361364454.pdfIn PDF document text
    • https://www.dynasil.com/wp-content/plugins/super-forms/uploads/php/files/0d2c7e34d8f4712a9af6f0d5fc9eaf5d/91128617406.pdfIn PDF document text
    • http://cristal-in.fr/userfiles/file/laviximaxijorivebirikep.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=android+to+iphone+transfer+photosPDF link annotation
    • http://crossfit28.com.s125853.gridserver.com/siteuploads/editorimg/file/62306074934.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_off0000d296.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD296 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000eaad.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEAAD 10528 bytes
SHA-256: f40929ee5cc397922ec697dd611b93ba1422779dc1a87870f4eb169eed5d0193
font_02_sfnt_off00010294.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10294 17404 bytes
SHA-256: 9b3184e3d018d55148989ca1a2e7c3459a902ebf3636ec36bd067a3fdbd002e1

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