Malicious PDF — malware analysis report

Static analysis result for SHA-256 bf9a38552abb6b5f…

MALICIOUS

PDF

87.9 KB Created: 2021-08-09 09:10:34 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 41c7da13bd1076a16afa23fd6ac56799 SHA-1: 20d532dd9cecca6a46de024fce575da3d729cb07 SHA-256: bf9a38552abb6b5f1ebecc054ae3a26306f5c470e4b2d1bc370032b6c5368115
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous links pointing to other PDF files hosted on compromised websites, indicating a link farm designed to distribute malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware delivery. The document's structure and the nature of the embedded URLs align with techniques used to obscure the true destination and evade initial detection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9972

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 http://auapp.ch/userfiles/files/mefuj.pdf In PDF document text
    • https://dewalt-naradi.cz/media/upload/editor/file/zimepavojupaveg.pdfIn PDF document text
    • https://couvreur-hautdoubs.fr/internet_new/images_et_fichiers//file/1775772254.pdfIn PDF document text
    • https://cananalimdar.com/wp-content/plugins/super-forms/uploads/php/files/2l8af5qbfnrtse0ulcn39s5grn/noluwanisupebajeruju.pdfIn PDF document text
    • https://www.mybizwebsites.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bbe5fd5d4a4---15973810698.pdfIn PDF document text
    • https://rhythmcprandfirstaid.com/wp-content/plugins/super-forms/uploads/php/files/c58580fdb16e78172669df92c05b6a1b/sunexewebisegovi.pdfIn PDF document text
    • https://deniz-sogutma.org/img/userfiles/file/99459302280.pdfIn PDF document text
    • http://opalbiosciences.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e3c11601989---pugamutimutos.pdfIn PDF document text
    • http://olech-rzeszow.pl/userfiles/file/90705473989.pdfIn PDF document text
    • https://africanresearchcenter.com/userfiles/file/wegewabaxopater.pdfIn PDF document text
    • http://villa-margherita.biz/userfiles/files/dafojev.pdfIn PDF document text
    • https://masterpieces-mallorca.com/wp-content/plugins/super-forms/uploads/php/files/f480408c235a297c61d27efa77bca0d0/26202862825.pdfIn PDF document text
    • http://gancza.pl/userfiles/file/nedugo.pdfIn PDF document text
    • http://kapalishakti.com/ckfinder/userfiles/files/24069538412.pdfIn PDF document text
    • https://phase1acoustics.com/wp-content/plugins/formcraft/file-upload/server/content/files/160cbb4b93288a---jurupanejo.pdfIn PDF document text
    • http://studionegro.net/userfiles/files/9358843309.pdfIn PDF document text
    • http://dansungsala.com/uploads/files/62611860263.pdfIn PDF document text
    • https://www.profiemg.cz/upload/ck/files/5164462305.pdfIn PDF document text
    • http://tano-cable.com/d/files/69585481423.pdfIn PDF document text
    • https://zweiund40.com/wp-content/plugins/super-forms/uploads/php/files/92otbaugno58c31uvf9bd6lonj/lazikavotudolaf.pdfIn PDF document text
    • https://arenda1s.ru/wp-content/plugins/super-forms/uploads/php/files/4a1345ad40581601e634a2e8e951f40e/filivajaxalekisapen.pdfIn PDF document text
    • https://marosme.ro/hirek/file/58459942296.pdfIn PDF document text
    • http://allaboutdowney.com/userimages/lurawolu.pdfIn PDF document text
    • https://www.huaikrachaohospital.go.th/assets/global/lib/ckfinder/userfiles/files/juwakesorifobame.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=what+did+ancient+egyptian+farmers+do+for+funPDF 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_off0000f5a2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5A2 11228 bytes
SHA-256: 6eefa268113ef532433c2e7a13ec09760da92f02a9bd2bc4daf7c4b0af555178
font_01_sfnt_off00010f9d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10F9D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000127af.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x127AF 15920 bytes
SHA-256: 9acadf9df6244237fe6663f1fdfc91c15e336cdc114bcda1bcccd5275ef54d29