Malicious PDF — malware analysis report

Static analysis result for SHA-256 51410666a59e98d4…

MALICIOUS

PDF

76.4 KB Created: 2021-09-16 19:50:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 7a5c91b9772b77f02657268a45d65003 SHA-1: 14df7b855d704884d10ad2df3c58e310d1f68d28 SHA-256: 51410666a59e98d4505cb443d424dec8b0af69016600329ea076bf0b6b1828a3
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was identified as malicious by ClamAV and an ML classifier, with multiple heuristics indicating it functions as a link farm pointing to compromised WordPress uploads and disposable hosting. The embedded URLs suggest a phishing or malware distribution scheme, likely involving redirection to malicious sites. No scripts were extracted, but the PDF structure and URL patterns are indicative of a common phishing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

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://inwebjor.ru/uplcv?utm_term=how+to+open+imac+in+recovery+mode PDF link annotation
    • http://gzcaifeilai.com/ckfinder/userfiles/files/202109050609043156.pdfIn PDF document text
    • http://www.nisbd.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613ea01a830c7---7104681531.pdfIn PDF document text
    • http://basaritarim.net/admin/editor_resim/file/zejusanodize.pdfIn PDF document text
    • http://luchetti.it/userfiles/files/20572539656.pdfIn PDF document text
    • http://closehorses.com/userfiles/file/sujoxusifavajanonofuri.pdfIn PDF document text
    • http://cs-web-design.de/ablage/userfiles/files/19170545059.pdfIn PDF document text
    • http://xn--eyt274i.com/upload/files/kaxewavawod.pdfIn PDF document text
    • http://lammensfilip.be/uploads/files/butidigidupi.pdfIn PDF document text
    • http://tangiahoang.com/skinkorea/Images_upload/files/nolerozafizulula.pdfIn PDF document text
    • http://restravel.ru/ckfinder/userfiles/files/92405914249.pdfIn PDF document text
    • https://eownauto.com/uploadpic/files/bupale.pdfIn PDF document text
    • http://argentum.com/wp-content/plugins/super-forms/uploads/php/files/buhhg3ov0bg4lk095071q45rbr/xejasi.pdfIn PDF document text
    • http://www.grifin.sk/files/2847232697.pdfIn PDF document text
    • https://ispartaprefabrik.com/ckfinder/upload/files/toguzuligidozipadigebari.pdfIn PDF document text
    • http://www.motionmantra.com/userfiles/files/duzujiz.pdfIn PDF document text
    • http://paulgraphics.paulsfashion.in/files/bomilamirex.pdfIn PDF document text
    • http://www.lifestaralberta.com/wp-content/plugins/formcraft/file-upload/server/content/files/16132c8f567d18---fatejizesimuva.pdfIn PDF document text
    • https://jf-orvalho.pt/userfiles/file/sapem.pdfIn PDF document text
    • http://atlonnuri.org/UpLoadImage/editer/files/80597794442.pdfIn PDF document text
    • https://kovtec.pl/eurostyl/photos/file/vokimavuloruzugepe.pdfIn PDF document text
    • http://www.radanhorse.com/resource/files/98834270421.pdfIn 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://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_off0000c53b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC53B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000dd52.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD52 10716 bytes
SHA-256: 91eade37aabea4f12af507f61c83b9bc326d579c49d21c5e50b67ecd86427261
font_02_sfnt_off0000f5ed.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5ED 17732 bytes
SHA-256: e11e7c3a6a4aeee409a1795376f07e4663a4308a3545e0b8254f70ad28a8df29