Malicious PDF — malware analysis report

Static analysis result for SHA-256 bf8c9191971b0701…

MALICIOUS

PDF

81.1 KB Created: 2021-09-09 15:43:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 2287c7e2ebc04b22bd78f5da71b6fd81 SHA-1: 21bcdb210abefff912187505d0bc0abd4c7d03eb SHA-256: bf8c9191971b070114cd600c293e85abf482ac124f6c60ee65b546f7900bfff1
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript, which is a common technique for executing malicious code. Several heuristics indicate the presence of a link farm pointing to compromised upload storage and disposable hosting, suggesting an attempt to host malicious content or phishing pages. The ClamAV detection and ML classifier strongly indicate malicious intent, likely related to phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://holcom-wd.holcom.vn/webroot/img/files/jikidogapizuf.pdf In PDF document text
    • https://autohausnschmidt.de/userfiles/file/90948768768.pdfIn PDF document text
    • http://deurwater.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139fdcb18e1b---pakudilozajizipasepum.pdfIn PDF document text
    • http://studio70.eu/userfiles/files/41130411658.pdfIn PDF document text
    • http://cardealer-space.com/js/upload/files/16223832214.pdfIn PDF document text
    • http://www2.grupoksl.com.br/js/ckfinder/userfiles/files/witibitanawefugupuziz.pdfIn PDF document text
    • http://virus-safe-zone.com/ckupload/files/29980904715.pdfIn PDF document text
    • https://taxforce.nl/userfiles/files/81903518482.pdfIn PDF document text
    • https://www.ferienhof-schneider.de/wp-content/plugins/formcraft/file-upload/server/content/files/16135116a45f99---9667518638.pdfIn PDF document text
    • http://nhasachnguyenvancu.com/Images_upload/files/rirotixoraperotux.pdfIn PDF document text
    • http://architettosirocco.it/userfiles/files/25536779472.pdfIn PDF document text
    • http://rencontres-icare.org/userfiles/file/jizemidokakevoludelaxebex.pdfIn PDF document text
    • https://justbuymeds.net/userfiles/file/boleri.pdfIn PDF document text
    • https://unicorn.mn/js/ckfinder/userfiles/files/sewerijatofop.pdfIn PDF document text
    • http://stlnsk.ru/uploads/file/zilalababakuxukabojisiv.pdfIn PDF document text
    • http://back2wood.de/userfiles/file/xafitetunewizasowajiwonog.pdfIn PDF document text
    • http://amuseonline.com/absite/userfiles/file/dinetupemojusitirosikam.pdfIn PDF document text
    • http://jcpingie.be/public/files/mokagojo.pdfIn PDF document text
    • http://nfraccon.org/userfiles/file/dodipesorasujojesu.pdfIn PDF document text
    • http://nhuaduongnhapkhauaz.info/upload/files/bigakigawutironuvekanuba.pdfIn PDF document text
    • https://alshaabcoop.com/userfiles/file/18225757942.pdfIn PDF document text
    • http://www.herbertvanderbrugghen.nl/draft/sufugekenibero.pdfIn PDF document text
    • http://www.ebsjosepirosamaria.com/wp-content/plugins/formcraft/file-upload/server/content/files/16135c1c51225e---85014491551.pdfIn PDF document text
    • https://www.cdsale.org.au/application/third_party/ckfinder/userfiles/files/weranudininoparunopod.pdfIn PDF document text
    • http://a-pluset.com/userfiles/nuzeburoxid.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=the+jungle+cruisePDF 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_off0000db52.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB52 10324 bytes
SHA-256: 2da460897ceb49d6691d4eb13410d714627058b7af9254f00e69604c6fd61a8d
font_01_sfnt_off0000f267.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF267 17132 bytes
SHA-256: 25f7fd78cdb197153a3c62836094270e64b7e8ebcbfad1c955df2c3fb3be588a
font_02_sfnt_off00011e93.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E93 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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