Malicious PDF — malware analysis report

Static analysis result for SHA-256 b668cdd59eb5d6f6…

MALICIOUS

PDF

78.8 KB Created: 2021-10-06 18:48:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 42ee2329bb5942d0af7bd00479522b75 SHA-1: ca4dcffd867ed78ce33d5ce67b6955e292dfac1e SHA-256: b668cdd59eb5d6f6c7180d4720d3a5661ad6b76ce9c5f4a0a4d0a0152f018e84
96 Risk Score

Malware Insights

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

The PDF contains a large number of links pointing to other PDF files hosted on various domains, many of which appear to be compromised or disposable. The ML classifier strongly flagged this PDF as malicious, and the heuristic firings indicate it's part of a link farm designed to distribute content. The primary attack pattern observed is the use of a link farm to lure users to potentially malicious content, consistent with phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 5

  • 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://thailonghoang.vn/upload/files/95708725527.pdf In PDF document text
    • http://coverybox.box8websites.com/ckfinder/userfiles/files/5919238942.pdfIn PDF document text
    • https://www.playitdirect.ca/ckfinder/uploadfiles/files/50835576683.pdfIn PDF document text
    • http://isotope3.pm-ural.com/uploads/files/71701442115.pdfIn PDF document text
    • https://adproissy.emailingmanager.com/uploads/editor/file/29198441768.pdfIn PDF document text
    • http://simonhoirup.dk/userfiles/file/18006623159.pdfIn PDF document text
    • http://myxroad.net/upload/userfiles/file///kofefakarigebupuzup.pdfIn PDF document text
    • https://maymac.info/userfiles/file/benatibibopifedon.pdfIn PDF document text
    • http://montpellier-business-plan.fr/mbp/upload/images/images/upload/ckfinder/xugepe.pdfIn PDF document text
    • https://royal-art.pl/uploads/userfiles/files/topelujivufosasodina.pdfIn PDF document text
    • http://escuelasfutbol8.com/docs/files/61812996974.pdfIn PDF document text
    • https://dmddsgn.com/wp-content/plugins/super-forms/uploads/php/files/7465da86febbea71ff5126cefa29ba69/sibid.pdfIn PDF document text
    • http://www.chp.pl/ckfinder/userfiles/files/wekug.pdfIn PDF document text
    • http://thueotodn.com/uploads/image/files/rugano.pdfIn PDF document text
    • http://esistore.de/userfiles/file/20479294218.pdfIn PDF document text
    • http://sinorarechem.com/upload/files/22509334899.pdfIn PDF document text
    • http://parmalab.it/userfiles/files/nizigavason.pdfIn PDF document text
    • https://girl0229960192.com/upload/users/files/xoxifoxazo.pdfIn PDF document text
    • https://studiecarriere.it/uploads/file/21572277943.pdfIn PDF document text
    • http://erkerlaender.de/wp-content/plugins/formcraft/file-upload/server/content/files/1613aa096dc136---25210714899.pdfIn PDF document text
    • http://xn--d1achljw0b.xn--p1ai/content/upload/78293546932.pdfIn PDF document text
    • http://transporteslaplata.com/imagenes_web/file/65748719903.pdfIn PDF document text
    • http://www.tecnotrefg.it/wp-content/plugins/formcraft/file-upload/server/content/files/1614b23440baaa---81676794574.pdfIn PDF document text
    • https://cbconsulting112.ca/userfiles/files/64453725611.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/ngfLrbzwjls/uplcv?utm_term=definition+of+the+word+consternationPDF 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_off0000cc99.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCC99 18676 bytes
SHA-256: 34cefed1c60cad4df0f2737c352ac0356571316ac65cdb9b20c6d3e5c7a5ff02
font_01_sfnt_off0000fc93.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC93 10616 bytes
SHA-256: f92e97f009a6a67039178ecd47026bf9e5cf4cfd7a4401223bf4038ceaff2d2b
font_02_sfnt_off000114e1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x114E1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1