Malicious PDF — malware analysis report

Static analysis result for SHA-256 6d41703a51c8426b…

MALICIOUS

PDF

96.2 KB Created: 2021-09-16 13:58:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: cb0aa605e87f28ee7b34b45102da7fdb SHA-1: 63345b778cec63130d6372ec6d49394bb78478ef SHA-256: 6d41703a51c8426b5ed7b5a5a2933858d9cdd5bc378479a3921572de24999d23
156 Risk Score

Malware Insights

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

The PDF contains numerous links to other PDF files hosted on various domains, many of which appear to be compromised or disposable. The ClamAV detection and ML classifier strongly indicate malicious intent, likely related to phishing or SEO spam. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' confirms the link farm nature, and the presence of 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' suggests these links point to content uploaded via compromised Content Management Systems.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9888

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://trystsalonri.com/images/file/zajiwovowuvaxav.pdf
    • http://www.hcibatiment.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1613ae5347e1f5---rujufafitadudemofubevorar.pdf
    • https://conexusinternational.com/ckfinder/userfiles/file/dibekoxujitewinifa.pdf
    • https://wheelmartthailand.com/image/upload/File/dajebawovubukokeza.pdf
    • http://camara.acessoainformacao.org/uploads/ckfinder/files/89723704861.pdf
    • http://www.findvoters.com/userfiles/file/65115829632.pdf
    • http://lineshare.net/upload/files/20210905164939.pdf
    • http://peetersinstallatietechniek.nl/upload/files/36474539013.pdf
    • http://filippodelvita.com/demo/userfiles/file/29886720686.pdf
    • http://kurskodkb.ru/page_edit/_samples/userfiles/files/lelev.pdf
    • https://kubermatkaplay.com/ckfinder/userfiles/files/goboxufajakerasodevojizow.pdf
    • https://tomas-music.com/contents/files/65973444975.pdf
    • http://kronospan-mofa.hu/editor_up/26099909043.pdf
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613b4e7fef4df---deriteluxiruzuvumanijilaz.pdf
    • http://jcon-aps.dk/userfiles/file/24713185599.pdf
    • http://futimisdev.com/userfiles/file/77541636241.pdf
    • https://ht-cooling-j3t.com/contents/files/29688525757.pdf
    • http://omeofest.eu/userfiles/files/jelijisumetikawi.pdf
    • https://undergroundtakeout.com/userfiles/file/17400180632.pdf
    • http://phanphoiongnhuahoasen.vn/upload/files/gusupuxupunu.pdf
    • http://belst.by/upload/file/93081651594.pdf
    • http://alsace.annuaire-regional.com/ckfinder/userfiles/files/59747554867.pdf
    • http://makaeximworld.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613f7d6fd2f54---jeruwagi.pdf
    • https://lrsdev.com/userfiles/file/76675761686.pdf
    • http://nd-58.ru/wp-content/plugins/super-forms/uploads/php/files/9d3237e37c9863d968f3f36fb76ec28d/79430090007.pdf
    • http://kmsenior.org/file/files/40294035036.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/YTWXjIUwRh0/uplcv?utm_term=essential+accounting+textbook+pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000110ca.bin
6db85f089515140acebe39324236259835011301f744939f0d4909c598673dbe
pdf-font-stream PDF embedded font (sfnt) at offset 0x110CA 18340 bytes
font_01_sfnt_off0001410b.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x1410B 16792 bytes
font_02_sfnt_off00015922.bin
a4fa835c240750c70fc9d4cfdc21e2b43e3104377f00704eecd27ab151f20f09
pdf-font-stream PDF embedded font (sfnt) at offset 0x15922 11112 bytes