Malicious PDF — malware analysis report

Static analysis result for SHA-256 21b157afcd5e155e…

MALICIOUS

PDF

111.8 KB Created: 2021-07-28 06:15:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: e4a88c6d83e481737199d463272b8420 SHA-1: b62ffc3f7b5c275bfe1f5649f9fb4856a7055e21 SHA-256: 21b157afcd5e155e46af1c431d53824c80838315ae9313f0ac9cdef334cd7c23
156 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics as malicious, including a critical ClamAV detection and an ML classifier. It contains a large number of links, many pointing to compromised CMS upload directories, suggesting it's designed to redirect users to malicious content. The presence of external URIs and link farm characteristics indicates a phishing or redirection attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9961

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://www.vibrationmonitoring.asia/wp-content/plugins/formcraft/file-upload/server/content/files/160a192a0c6bc2---92975674380.pdf In PDF document text
    • https://aryaayur.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d1d06674c1b---visuz.pdfIn PDF document text
    • http://dinskayarealty.ru/media/file/74538421235.pdfIn PDF document text
    • http://www.alex-vasilkov.ru/images/wisdom/file/9034608228.pdfIn PDF document text
    • http://ilovegabal.net/fckeditor/_upload/file/43871628218.pdfIn PDF document text
    • https://suma.ca/upload/editor/file/66357262039.pdfIn PDF document text
    • http://aaaexpressheating.com/userfiles/file/sogawuxetujuvoduni.pdfIn PDF document text
    • http://jshtextile.com/UserFiles/file///befiwagunoxuv.pdfIn PDF document text
    • http://chongros.com/userData/board/file/nepenudibofilebolana.pdfIn PDF document text
    • https://art4you.sk/editor_uploads/system/files/pajusafagofefipikuri.pdfIn PDF document text
    • http://mountmedpharmacy.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160c43251d6c8f---9332899675.pdfIn PDF document text
    • https://hopefor.today/wp-content/plugins/super-forms/uploads/php/files/7f705e6e379a11f38a0a3eb29d279cff/33831961766.pdfIn PDF document text
    • https://newat.ru/wp-content/plugins/super-forms/uploads/php/files/5ae3422e52a9041b39ee56b1a1d94520/79938018843.pdfIn PDF document text
    • http://artechq8.com/beta/uploads/files/liworusejixolosabisux.pdfIn PDF document text
    • http://acetuitioncentre.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160bc8ae6506ec---rinosudavojazal.pdfIn PDF document text
    • https://www.hamburgeriaagricola.com/wp-content/plugins/super-forms/uploads/php/files/pkpn9asc6lh6qv5gk35v860vv4/votatevogitubonax.pdfIn PDF document text
    • http://melissajacksonmd.com/wp-content/plugins/formcraft/file-upload/server/content/files/16078c6e47f513---roxavomiwexipekis.pdfIn PDF document text
    • https://loan-financial.com/wp-content/plugins/super-forms/uploads/php/files/bdfa6fab39c66e7a2332cf39ac5e9c99/fepin.pdfIn PDF document text
    • https://ahi.com.ua/wp-content/plugins/super-forms/uploads/php/files/c1d0e0487ff583011252567cfb35bf56/fomogol.pdfIn PDF document text
    • http://wbbray.com/wp-content/plugins/formcraft/file-upload/server/content/files/16070c3ce8cf1e---sufudage.pdfIn PDF document text
    • https://speakingparrot.com/upload/ckfinder/files/71341751039.pdfIn PDF document text
    • https://digireg.gr/upload/41126860693.pdfIn PDF document text
    • https://mcq-exambd.com/app/webroot/ckfinder/userfiles/files/12689716809.pdfIn PDF document text
    • https://www.sistemkabin.com/ckfinder/userfiles/files/37273853357.pdfIn PDF document text
    • https://autotronics.vn/userfiles/file/32000640874.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BkSY9tpko7c/uplcv?utm_term=walmart+assessment+test+answers+2018+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_off000143dd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x143DD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00015bef.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15BEF 22336 bytes
SHA-256: 72d0331523654a751efbbbade26d174f99ecb5ec01cc7940f8fe963c7890787a
font_02_sfnt_off000195b5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x195B5 11028 bytes
SHA-256: 00c224b127dbe9552c7d841d5dbed3e36ea16ce9eebdf1160e5f6e9a150b8644

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