Malicious PDF — malware analysis report

Static analysis result for SHA-256 ac73aa9855a98606…

MALICIOUS

PDF

73.8 KB Created: 2021-09-04 20:03:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: cfede970c5cb934b597a7d852f624330 SHA-1: 88e6e1c20bcfd32641954f16608b1e0bac9adf3c SHA-256: ac73aa9855a98606392149688658369dd96077192d50b5a3a5a4116359ebd6a1
156 Risk Score

Malware Insights

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

This PDF was flagged by ML and ClamAV as malicious, indicating it likely exploits a vulnerability or serves as a phishing lure. The presence of numerous links, many pointing to compromised CMS upload directories or disposable hosting, suggests it functions as a link farm to distribute further malicious content or redirect users to phishing sites. The document body is heavily obfuscated and unreadable, providing no direct textual clues to its specific purpose.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9914

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 http://jpind.pl/userfiles/file/bagasudi.pdf In PDF document text
    • https://associazionedynamica.it/uploads/file/19893988635.pdfIn PDF document text
    • https://theshairpodcast.com/wp-content/plugins/super-forms/uploads/php/files/6c3b072e7b8e05903b981e75812fd0ca/94892106341.pdfIn PDF document text
    • https://propbrains.com/wp-content/plugins/super-forms/uploads/php/files/cam7ed59ndavjiikjjup4mq237/63309173569.pdfIn PDF document text
    • http://ychnjl.net/userfiles/files/59674901126.pdfIn PDF document text
    • http://www.lbf-cosmetics.com/website/wp-content/plugins/formcraft/file-upload/server/content/files/1609d295137b28---36964573952.pdfIn PDF document text
    • https://jfefood.com/wp-content/plugins/super-forms/uploads/php/files/fcb7b151c7f774012e7fd20256954752/rigofogotivuterokudetevo.pdfIn PDF document text
    • http://avstralianature.ru/ckfinder/userfiles/files/97492565559.pdfIn PDF document text
    • http://hmed.vn/upload/files/mitepolanajuwovawod.pdfIn PDF document text
    • http://dichvu12h.net/userfiles/file/zilavita.pdfIn PDF document text
    • https://wacee.net/wp-content/plugins/formcraft/file-upload/server/content/files/1609402115ba7c---metelososiwofunurowinib.pdfIn PDF document text
    • https://home18.ru/wp-content/plugins/super-forms/uploads/php/files/c9847d11157d3ff5322c3e6fc1b0246a/zugederopowimu.pdfIn PDF document text
    • https://datatech-int.com/userfiles/file/tivikexuvuwuxifi.pdfIn PDF document text
    • https://gz-topstar.com/wp-content/plugins/super-forms/uploads/php/files/44486df6fbb609d5229d94fa9df8b9e9/78795372699.pdfIn PDF document text
    • http://anhuifan.com/upload_fck/file/2021-6-22/20210622170016427820.pdfIn PDF document text
    • http://lavera.it/wp-content/plugins/formcraft/file-upload/server/content/files/160a0ccfeb3980---17333087220.pdfIn PDF document text
    • http://mijneigenlift.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160995c608c72d---wilinoniwivu.pdfIn PDF document text
    • https://www.pollackmihalyiskola.hu/ckfinder/userfiles/files/52551000532.pdfIn PDF document text
    • http://somersetcountybar.org/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/11436497080.pdfIn PDF document text
    • https://www.amiunaorchestra.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1607afad52b330---rogudom.pdfIn PDF document text
    • https://tectrongim.com/uploads/files/kejipifekozarimoledexum.pdfIn PDF document text
    • http://studiogiamberardino.it/userfiles/files/vagexalekukip.pdfIn PDF document text
    • https://alternatifhosting.com/calisma2/files/uploads/55021660162.pdfIn PDF document text
    • http://sbsinternationalschool.org/sbsisnew/userfiles/file/15249579425.pdfIn PDF document text
    • https://www.audioclinica.pt/wp-content/plugins/super-forms/uploads/php/files/96okj832al7e2f7eq0vulldt5s/gifawatujineput.pdfIn PDF document text
    • https://akdenizokullari.k12.tr/wp-content/plugins/super-forms/uploads/php/files/al0hfp67e6ofp6ru4hu1l8s34f/54475475487.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/DOqCt-cVA4I/uplcv?utm_term=zellweger+syndrome+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_off0000c057.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC057 10652 bytes
SHA-256: a41bdb445bcb3cccb1028162781226a3786ca0f21aeb53ed1ef3ae93154f605a
font_01_sfnt_off0000d88c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD88C 15904 bytes
SHA-256: e987de54a2bf3546db8dc2472e1aee5ff265e66737c0baa39732cd059c2aecd9
font_02_sfnt_off00010143.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10143 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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