Malicious PDF — malware analysis report

Static analysis result for SHA-256 a1c9305f4173898a…

MALICIOUS

PDF

85.4 KB Created: 2021-09-07 03:49:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 23ff20d70af60af6d388d06a68367295 SHA-1: 875ff5f7ecfe19df79919ef6e4163c299152f3ae SHA-256: a1c9305f4173898a87c23db066cf63ca81b3d09efe674cc42b9fdd739eb0c0db
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous embedded URLs, many of which point to compromised WordPress sites or disposable hosting, forming a link farm. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The primary attack pattern involves luring the user to click on these links, which could lead to exploitation or credential theft.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://suhrsmad.dk/wp-content/plugins/formcraft/file-upload/server/content/files/160ba063d50f30---37122286165.pdf In PDF document text
    • http://lukinserv.hu/file/14614180379.pdfIn PDF document text
    • http://constructionone.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1609a7dbd2aa30---70239406332.pdfIn PDF document text
    • https://spheresignal.com/app/webroot/userfiles/files/vevulobazunuwujusanateke.pdfIn PDF document text
    • https://gpagroup.in/wp-content/plugins/formcraft/file-upload/server/content/files/160743743c53f7---risosejuvevawosusos.pdfIn PDF document text
    • https://www.clubmanizales.com.co/wp-content/plugins/formcraft/file-upload/server/content/files/1606ca49dbbb73---xaxixofafawevenex.pdfIn PDF document text
    • https://k-kompany.ru/wp-content/plugins/super-forms/uploads/php/files/7683fed049baf7aea4f5a7a4063ef6ab/tanovalepeneruvimaxi.pdfIn PDF document text
    • http://humanitool.ru/userfiles/file/19756552504.pdfIn PDF document text
    • https://kfz-gutachter-oliver-schiller.de/wp-content/plugins/formcraft/file-upload/server/content/files/160c8b70375813---ramijuzugifomitimezotorap.pdfIn PDF document text
    • http://grafiport.com/userfiles/file/dilozawijuxuvamupuwuxa.pdfIn PDF document text
    • https://a-pointpro.com/cms/ckfinder/userfiles/files/wuligekaluxesilirumu.pdfIn PDF document text
    • https://nceptionsolutions.com/wp-content/plugins/super-forms/uploads/php/files/3e80cc07f9852b9a5dfc6d888dd3e0c0/xilafofami.pdfIn PDF document text
    • http://royalgroup.at/tmp/pumawatarifuja.pdfIn PDF document text
    • http://entone.es/wp-content/plugins/super-forms/uploads/php/files/fcca6ac0d3b93785e3e6fb0bf74873b7/7740546793.pdfIn PDF document text
    • http://www.cbs-emballages.com/upload/file/tikivesivuxuwekogazox.pdfIn PDF document text
    • http://familiehollander.nl/images/uploadedimages/file/7116075770.pdfIn PDF document text
    • http://janjoling.com/public/ckfinder/userfiles/files/pajemexelipuxitufufev.pdfIn PDF document text
    • https://vuaship.com/wp-content/plugins/super-forms/uploads/php/files/i2itcin2ag66b68j6h16ei79ii/73044626787.pdfIn PDF document text
    • http://akcjonariusz.com/UserFiles/file/mexoze.pdfIn PDF document text
    • http://www.acefence.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ff37ee31f45---95988327543.pdfIn PDF document text
    • https://wcdt.co.th/wp-content/plugins/super-forms/uploads/php/files/fn4dd7fu0a7no7g8q31m9cndai/86550834091.pdfIn PDF document text
    • http://baikalspring.ru/ckfinder/userfiles/files/60860567508.pdfIn PDF document text
    • http://www.misshandicap.ch/wp-content/plugins/formcraft/file-upload/server/content/files/1607caf69a2e66---23515437321.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/GLLx1DTH0VQ/uplcv?utm_term=actividades+en+ingles+pdfPDF 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_off0000e58b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE58B 19668 bytes
SHA-256: 097ad7da4b3980c7a5beeee1b93d57d7af4c373c363ab5180552be1b7115eec3
font_01_sfnt_off0001177f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1177F 10624 bytes
SHA-256: 41e147b9585f51d0ae0bb45069dd2f25a61141f1edaee486268b3223231befe5
font_02_sfnt_off00012fbf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12FBF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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