Malicious PDF — malware analysis report

Static analysis result for SHA-256 25d531e12de8e5df…

MALICIOUS

PDF

77.3 KB Created: 2021-06-09 08:51:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-24
MD5: 135ae0e6140888bad18a803191039cd3 SHA-1: e2d26d5a8b5d7ff9ad1376126e724cc8f42fb164 SHA-256: 25d531e12de8e5dfb2dc488500eea1f1a85317e92a6a8c875af76d6b1ef136ba
156 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous links, many pointing to compromised WordPress sites, suggesting it functions as a link farm to distribute phishing or malware. The document body is heavily obfuscated and contains metadata indicating it was generated by wkhtmltopdf, a tool often used to create PDF documents from web content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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 https://cructi.ru/uplcv?utm_term=break+even+point+sample+problems PDF link annotation
    • http://discoveryenglish.org/wp-content/plugins/formcraft/file-upload/server/content/files/160a3d3d2ac6b3---vuzipuvunigobuvifuremew.pdfIn PDF document text
    • https://alshamiltrading.com/alshamilfiles/file/4346646372.pdfIn PDF document text
    • http://www.scmphotography.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160bf25f8e4618---nozomaluwinasewomikogina.pdfIn PDF document text
    • https://sumangold.net.vn/wp-content/plugins/super-forms/uploads/php/files/1op5v465vm773u7mm1pvljdcjk/xefilafixet.pdfIn PDF document text
    • https://www.skyline-recruiting.com/wp-content/plugins/super-forms/uploads/php/files/4bd23fa5bcaaa13a1cec90d3d7db53d3/48052718786.pdfIn PDF document text
    • http://2ds-creations.fr/userfiles/file/17492850745.pdfIn PDF document text
    • https://thealloywheelcentre.co.uk/wp-content/plugins/super-forms/uploads/php/files/681669150fb49a098f9c4df5b58c80ff/44093912643.pdfIn PDF document text
    • http://domeinbeverdonk.be/assets/files/file/niget.pdfIn PDF document text
    • http://steclotildehorton.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1608ac071505b3---lojesasujipobasadodu.pdfIn PDF document text
    • https://gtsonline.nl/wp-content/plugins/super-forms/uploads/php/files/69vjbsg6ls2kre2emglvcq5d5p/xirozelimibupalenob.pdfIn PDF document text
    • https://ventana-sur.com/wp-content/plugins/formcraft/file-upload/server/content/files/16099dbbc0bfef.pdfIn PDF document text
    • http://pck.malopolska.pl/wp-content/plugins/super-forms/uploads/php/files/bc5d4e70faaaf6301f219a0f09582871/34727929791.pdfIn PDF document text
    • https://www.edutechusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b2f116311a3---wuxobepiparelapufeti.pdfIn PDF document text
    • https://prtl.pl/userfiles/file/25155220025.pdfIn PDF document text
    • https://www.mclarenpress.com/wp-content/plugins/formcraft/file-upload/server/content/files/16082c6b03c7e5---23087468103.pdfIn PDF document text
    • http://nc2e.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160c0256ce3f1b---49999782202.pdfIn PDF document text
    • https://macleanpinesdrivingschool.com.au/wp-content/plugins/super-forms/uploads/php/files/c25e269da3a7a1e9b96b8439dc28c9a5/wumulukarajenesopiku.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ef56.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF56 5276 bytes
SHA-256: 2e88f91fbaa750f5a416f00809fcbe6790d4a97f3bb24ec4a0664d0d266ceee4
font_01_sfnt_off00010134.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10134 11660 bytes
SHA-256: 62b80429b5a5cf334611427fc0d837239267e0552f29118298a9782182b11d09