Malicious PDF — malware analysis report

Static analysis result for SHA-256 d8c16544f350272d…

MALICIOUS

PDF

77.7 KB Created: 2021-09-19 17:15:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 081329d39baa032ca36c89dd3cb419a3 SHA-1: 8c64c5309d7fef461239401bca0dac32f52fc097 SHA-256: d8c16544f350272d41ba91a9b52617f594cded86e2197b06ea8832fff0404efe
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 phishing or trojan threat. It contains a large number of embedded URLs, many of which point to compromised WordPress sites or disposable hosting, suggesting a link farm designed to redirect users to malicious content. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9908

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=ppsspp+new+version+apk PDF link annotation
    • http://seyrimerdin.com/userfiles/file/84475331944.pdfIn PDF document text
    • http://navigator-nsk.ru/userfiles/file/26483562827.pdfIn PDF document text
    • https://ap-qatar.com/userfiles/files/temawoxonuwisugajo.pdfIn PDF document text
    • https://ferest.ro/imagini_ws/2914983895.pdfIn PDF document text
    • http://grafiport.com/userfiles/file/8372966320.pdfIn PDF document text
    • http://jeanchapleau.com/userfiles/file/86140716633.pdfIn PDF document text
    • http://vigova.com/Images_upload/files/94572541168.pdfIn PDF document text
    • http://www.nbrownies.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161384f9c92975---25208004149.pdfIn PDF document text
    • http://a-range.ru/wp-content/plugins/formcraft/file-upload/server/content/files/161331b5af1f2d---wixotaturebirajeworom.pdfIn PDF document text
    • https://ganganagardentist.com/userfiles/file/tonifuvuxib.pdfIn PDF document text
    • https://moderator.lt/components/com_mijoshop/opencart/image/data/files/fesagujukudisen.pdfIn PDF document text
    • http://elskup.pl/images/assets/file/lisukaki.pdfIn PDF document text
    • http://clubselectionvoyages.net/images/file/vibijeniwopikejepeza.pdfIn PDF document text
    • http://topspeed4wd.com/ckfinder/userfiles/files/81969835334.pdfIn PDF document text
    • https://stepweystudy.com/ckfinder/userfiles/files/gezirelizedeza.pdfIn PDF document text
    • https://aptitudeclass.com/ckfinder/userfiles/files/rupiramidu.pdfIn PDF document text
    • http://www.trimbleexpress.sk/wp-content/plugins/formcraft/file-upload/server/content/files/16138c2c8eb8f2---kuravat.pdfIn PDF document text
    • http://rudolphi.nu/userfiles/file/90023472762.pdfIn PDF document text
    • http://honghuibio.com/d/files/gofitilimekuga.pdfIn PDF document text
    • https://mywayrtk.com/userfiles/file/kuratupu.pdfIn PDF document text
    • http://sportsbettingconsultants.net/cote_dor_import/admin/ckfinder/userfiles/files/66136877918.pdfIn PDF document text
    • http://yushendesign.com/images_fck/file/1632049643.pdfIn PDF document text
    • http://maxitelt.no/wp-content/plugins/formcraft/file-upload/server/content/files/1613923016c3b1---motapuwa.pdfIn PDF document text
    • https://baconbites.com/wp-content/plugins/super-forms/uploads/php/files/e2pq3lqpjrfeu9smp8u0gdqhk6/38179335860.pdfIn PDF document text
    • http://falconfam.com/ckfinder/userfiles/files/85335098647.pdfIn PDF document text
    • https://superpart.com/files/daziwenofisajenu.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_off0000cf09.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCF09 10348 bytes
SHA-256: 4c7f710b8438002fed839c4e5ffca6d9a21579b79f00cc1f1100062dc560e057
font_01_sfnt_off0000e697.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE697 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000fea9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFEA9 16516 bytes
SHA-256: 4c77daac15a55c0ae505c5a67bd7c3aa753b87cc15e029581efbbeaa250c59b3