Malicious PDF — malware analysis report

Static analysis result for SHA-256 9a40932b21b18e17…

MALICIOUS

PDF

85.7 KB Created: 2021-09-11 22:55:00 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 50394624fb09b9ade1ac1feeb5ad5bb4 SHA-1: 91464af696de92b9a50d40fab72247eb4ae94179 SHA-256: 9a40932b21b18e177ec8f1039fbc74eb5e15322428c8a64aef2c0b7bbb3b66b6
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised CMS upload directories or are part of a link farm hosted on disposable domains. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution through these links. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing content but serving as a container for the malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://stallion-international.com/userfiles/file/5419710626.pdf In PDF document text
    • http://af.ssla.ru/images/fornews/files/seravetulu.pdfIn PDF document text
    • https://myhoorayhealth.com/wp-content/plugins/super-forms/uploads/php/files/cf0d0026ca426e8b4014dc06d0359c3f/viledusibixu.pdfIn PDF document text
    • https://www.eos.org.eg/ckfinder/userfiles/files/wupujufokorobeduja.pdfIn PDF document text
    • http://le-bouquet.be/userfiles/files/juwukodigosi.pdfIn PDF document text
    • http://infrabud.eu/fckpliki/file/77407655601.pdfIn PDF document text
    • https://viboot.traigiongthuha.com/ckfinder/userfiles/files/70890026707.pdfIn PDF document text
    • http://generale-bureautique.fr/gdb/files/file/mobonuwovutezuvawe.pdfIn PDF document text
    • https://gmnavarra.es/ckeditor/files/8721186756.pdfIn PDF document text
    • http://lamorenj.com/userfiles/files/xemopiw.pdfIn PDF document text
    • http://accurateverdicts.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613ab4262d74c---65567218655.pdfIn PDF document text
    • https://choiceenergynetwork.com/wp-content/plugins/super-forms/uploads/php/files/0f4e54362d5d0f6aebee2ff0bff7617e/lulago.pdfIn PDF document text
    • http://xn--80affcyoc0ac1f6a.xn--p1ai/admin/modules/ckeditor/ckfinder/userfiles/files/xowegimelavew.pdfIn PDF document text
    • https://motionslam.com/wp-content/plugins/super-forms/uploads/php/files/2ecb5152679e7a6f8c39e2a29ed0c73e/68109919776.pdfIn PDF document text
    • http://deeringbayrealestate.com/userfiles/files/temifotigefuzesidujesoje.pdfIn PDF document text
    • https://www.truck-transport.com/ckfinder/userfiles/files/libasegoluvemok.pdfIn PDF document text
    • http://dichvuhieuchuan.com/upload/files/towefemoketabag.pdfIn PDF document text
    • https://pass-eco-energies.com/ckfinder/userfiles/files/vedewe.pdfIn PDF document text
    • http://bkmarine.net/ckfinder/userfiles/files/1630755130.pdfIn PDF document text
    • https://taksis.lv/taksis/userfiles/file/85699278464.pdfIn PDF document text
    • http://aeskulap24h.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613c70f12232f---mitixevuwaj.pdfIn PDF document text
    • http://iccjsc.vn/images/uploads/files/xumesudezididi.pdfIn PDF document text
    • http://heimundsicherheit.de/userfiles/file/11670088334.pdfIn PDF document text
    • https://osikovo.eu/webroot/img/content/files/47469293825.pdfIn PDF document text
    • https://asthasupermarket.com/userfiles/file/kududewesarazoxunimarudin.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BvfzZFkJO3s/uplcv?utm_term=instagram+all+version+androidPDF 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_off0000e9e9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE9E9 10608 bytes
SHA-256: 8cea8437407e17a1c3c776da89e746480fe6e76e0df032fb6aae3789af185ef3
font_01_sfnt_off000101e7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x101E7 18292 bytes
SHA-256: 9a9ba866494f68b50723a530c7892d2268adf3c38b5d9d4cc0a1d05954727044
font_02_sfnt_off0001313b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1313B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1