Malicious PDF — malware analysis report

Static analysis result for SHA-256 835f55c0121395db…

MALICIOUS

PDF

69.0 KB Created: 2021-09-27 13:53:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 7e8e2634ebee392689f9d401cad7a1fd SHA-1: ab0823c0545db6ccbc3d919ca85b79a5270ee96e SHA-256: 835f55c0121395db9f897ddca50d9f342e2cb5fe56b5bed544acb8d813cacf24
156 Risk Score

Malware Insights

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

The PDF contains numerous external links, many of which point to compromised CMS upload directories, suggesting a phishing or malicious redirection scheme. The ML classifier and ClamAV detection strongly indicate malicious intent, likely to lure users to malicious sites or download further malware. The document body is heavily obfuscated and unreadable, providing no direct content-based clues.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

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 http://caacoding.net/wp-content/plugins/formcraft/file-upload/server/content/files/1614473ca26ae1---mubikiwogitibezafegixo.pdf In PDF document text
    • https://olterus.org/contents/files/70975998229.pdfIn PDF document text
    • https://mauspro.net/upload/files/27591014299.pdfIn PDF document text
    • http://vivo-mebel.ru/upload/file/34853289644.pdfIn PDF document text
    • http://imoroz.by/upload/file/lofoladokosuwidavibog.pdfIn PDF document text
    • https://sammycar.ch/sammy/sites/default/sammyfiles/newsletterfile/60969196074.pdfIn PDF document text
    • http://gadkowski.pl/repository/filemanager/file/83777774888.pdfIn PDF document text
    • http://redondoclassicburger.com/uploads/files/64073573269.pdfIn PDF document text
    • http://pumarecovery.com/userfiles/files/77624748986.pdfIn PDF document text
    • https://www.hauptsache.cc/wp-content/plugins/formcraft/file-upload/server/content/files/1613238056a678---bekawiri.pdfIn PDF document text
    • https://www.caesarstravel.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614622e4732eb---nivikuj.pdfIn PDF document text
    • http://tataservice.it/userfiles/file/bipalofajavowemixosora.pdfIn PDF document text
    • http://lotuscourtpune.com/wp-content/plugins/super-forms/uploads/php/files/1cc0809900b973a647a1c6fb6447a809/gafumidigosij.pdfIn PDF document text
    • http://abimobiliare.pl/pliki/File/59403199051.pdfIn PDF document text
    • http://timebymtm.com/upload/files/najuvosuzusokiwe.pdfIn PDF document text
    • http://dalaichau.com/files/gadoguwunetivikamevomu.pdfIn PDF document text
    • https://clinicaabrahaoosta.com.br/ckfinder/userfiles/files/vusajakokig.pdfIn PDF document text
    • http://nguyenthaotech.com/upload/files/95386434706.pdfIn PDF document text
    • http://wxmx.cn/upload/ckimg/files/202109200103144674.pdfIn PDF document text
    • http://danies.ru/ckfinder/userfiles/files/koximig.pdfIn PDF document text
    • http://parbatsamajjapan.com/img/files/files/bezixofijexovawe.pdfIn PDF document text
    • http://abwwilson.com/uploads/files/24804215949.pdfIn PDF document text
    • https://t2sc.me/userfiles/81140293147.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=euphoryaa+2017+watch+onlinePDF 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_off0000b0a2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB0A2 14412 bytes
SHA-256: ef53d742094c0adaa4d3e479abdb14317e293a1e3ef7cf6b7d5dc03a413ab8e7
font_01_sfnt_off0000d4c3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD4C3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000ecda.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xECDA 10928 bytes
SHA-256: 13bf9c089d3fb1ec221d0c80ae3f7ddca207459874d677a7845d64fc186bced5