Malicious PDF — malware analysis report

Static analysis result for SHA-256 31a8d38bfe232fac…

MALICIOUS

PDF

69.2 KB Created: 2021-10-04 03:33:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 10f5fbd8e24c4b7fad8abea73fd4458e SHA-1: 70010114cfc18682a9ec40484984d5cadccf6e75 SHA-256: 31a8d38bfe232fac76a2d85ca4e0e32de1a001834860686bec0f6ffd6e74b722
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 CMS upload storage or disposable hosting, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or distributing further malware. The document body is unreadable, but the heuristic firings and URL analysis are sufficient to determine the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

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://ketchas.ru/uplcv?utm_term=the+meaning+of+obscurity PDF link annotation
    • http://haozuowenwang.com/imagefiles/file/pemejab.pdfIn PDF document text
    • https://branches.armz.ru/media/File/32692471624.pdfIn PDF document text
    • http://hagelkonzept.de/userfiles/file/51611870071.pdfIn PDF document text
    • https://lasanisports.com/files/gematugorasalivo.pdfIn PDF document text
    • https://samsungdvmklima.com/upload/ckfinder/files/silaziwadejabowipuget.pdfIn PDF document text
    • http://polaryachtmanufactory.com/res/wysiwyg/file/jipilavesowefavepuxavu.pdfIn PDF document text
    • https://sukhayurveda.in/userfiles/file/80982435381.pdfIn PDF document text
    • http://www.peplex.it/wp-content/plugins/formcraft/file-upload/server/content/files/1613fee8884882---94366538742.pdfIn PDF document text
    • https://ksmt.edu.np/assets/ckfinder/userfiles/files/90148733646.pdfIn PDF document text
    • http://lsbwg.com/ckfinder/userfiles/files/20210901/1131102604.pdfIn PDF document text
    • https://geneticapanama.com/userfiles/file/75390616452.pdfIn PDF document text
    • https://iphonerepairservice.nl/app/webroot/files/userfiles/files/gonovikiritalino.pdfIn PDF document text
    • http://hengfengpaper.com/filespath/files/20210908031915.pdfIn PDF document text
    • http://vekosgroup.ru/userfiles/file/92022592179.pdfIn PDF document text
    • http://saatgaamkansarasamaj.com/admin/uploads/files/11147952821.pdfIn PDF document text
    • https://hylyt.co/wp-content/plugins/super-forms/uploads/php/files/edb5058389363ea2f85f6e4058e24c18/96797361640.pdfIn PDF document text
    • http://iowatriallawyer.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/gudas.pdfIn PDF document text
    • http://agataklimowska.pl/userfiles/file/nebiveraduxevegekugagi.pdfIn PDF document text
    • http://umffz21.ru/admin/ckfinder/userfiles/files/dopuloduboworavoxokakuxi.pdfIn PDF document text
    • http://mvsexpo.ru/admin/ckfinder/userfiles/files/jodakobibuwita.pdfIn PDF document text
    • http://mvsexpo.ru/admin/ckfinder/userfiles/files/fedizazuxe.pdfIn PDF document text
    • https://vuaship.com/wp-content/plugins/super-forms/uploads/php/files/le7n8i8fo2jrrlsrvcsjk4phvs/mopamezowogeleto.pdfIn PDF document text
    • https://ms2oke.com/contents/files/5513689766.pdfIn PDF document text
    • https://mandalaconfeccao.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1615a1bb506c87---90346221234.pdfIn PDF document text
    • http://delve-cr.com/uploads/kufivumirukimu.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_off0000b167.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB167 14624 bytes
SHA-256: d5e540b3f3ce9e910fee4704f6eda9e6abd18333116c570ed720b36b0e393708
font_01_sfnt_off0000d5e9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD5E9 11052 bytes
SHA-256: a4ddd1deb026834b927fdc916c2669e2537439d1e30e49c9492e26d98db7914b
font_02_sfnt_off0000ef87.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF87 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1