Malicious PDF — malware analysis report

Static analysis result for SHA-256 23de15ff3caa800c…

MALICIOUS

PDF

77.0 KB Created: 2021-09-07 17:07:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 1c42b3107c68807af2e754cc1c872150 SHA-1: 2251149724209a7183525f44030909c09de86dce SHA-256: 23de15ff3caa800cc31905ac49f9679228098d578b0d57870e2778e181bbfaf8
96 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs pointing to compromised WordPress sites, indicating a link farm designed to redirect users to malicious content. The ML classifier strongly flagged this PDF as malicious, and the heuristics indicate it's part of a link farm on disposable hosting, likely used for SEO poisoning or phishing campaigns. No scripts were extracted, but the primary attack pattern involves directing users to external malicious resources.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

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://infrive.ru/uplcv?utm_term=glow+worm+energy+15r+user+manual PDF link annotation
    • https://evocative.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160b583b67b45f---kepodi.pdfIn PDF document text
    • https://alihuata.com/userfiles/file/jukukit.pdfIn PDF document text
    • http://www.nandomoraes.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16078eaaf3b4e3---rugujetibulukexixefuvemix.pdfIn PDF document text
    • https://kfz-gutachter-oliver-schiller.de/wp-content/plugins/formcraft/file-upload/server/content/files/160896b5dd2965---vozavoxuw.pdfIn PDF document text
    • http://kaplanpm.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ba8cb509d22---ximanerisolufanovixepafem.pdfIn PDF document text
    • https://clinicscrm.com/img/files/16357246708.pdfIn PDF document text
    • https://nnkcreations.com/userfiles/file/13481047170.pdfIn PDF document text
    • https://www.mybizwebsites.com/wp-content/plugins/formcraft/file-upload/server/content/files/16086ea611920d---kenafometewud.pdfIn PDF document text
    • https://fmpride.com/wp-content/plugins/super-forms/uploads/php/files/7fbcb5242666e4e13c4368898af86054/xifefowopo.pdfIn PDF document text
    • http://ketnoikienthuc.com/upload/files/54377203513.pdfIn PDF document text
    • http://macro-e.com/app/webroot/userfiles/files/fofivivanisisupapija.pdfIn PDF document text
    • https://ivfnna.gr/wp-content/plugins/super-forms/uploads/php/files/1004e0bb86ce8925c2bed10ef5eff712/tezogubafaritaxosuza.pdfIn PDF document text
    • https://twinslock.com/ckfinder/userfiles/files/pogev.pdfIn PDF document text
    • http://cokhihoaiduc.com/uploads/files/dibitotukedul.pdfIn PDF document text
    • https://led7.ru/file/78850655875.pdfIn PDF document text
    • https://evergreencans.com/userfiles/file/39545280659.pdfIn PDF document text
    • https://yssnewlessons.org/UserFilesTwo/file/73963399478.pdfIn PDF document text
    • https://trungtammatnamviet.vn/upload/files/vojulumetumebir.pdfIn PDF document text
    • https://ukdirectremovals.com/wp-content/plugins/super-forms/uploads/php/files/10e052b44451496bd5dd8c13f51c4eba/kivoduxepuwadurudoji.pdfIn PDF document text
    • http://jr-bang.com/uploadfiles/20210620221735.pdfIn PDF document text
    • http://www.kissdocs.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16075ab832c303---15830790235.pdfIn PDF document text
    • http://biirbeh.mn/images/content/file/zaludonapuvu.pdfIn PDF document text
    • https://la-klamm.org/Files/files/zekerogogugukisutezodajut.pdfIn PDF document text
    • https://www.frontierexim.com/wp-content/plugins/super-forms/uploads/php/files/4sl4r240777hlfptd4ipfgmqgp/30048964190.pdfIn PDF document text
    • 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_off0000ca10.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCA10 16784 bytes
SHA-256: 0618af137d7ba272edfc9085f6de33b13fc52eacc38a32910e979d6a99b86ec9
font_01_sfnt_off0000f58b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF58B 10784 bytes
SHA-256: d4ca0b7af9187aa6fb01178e9d12e30f0b4eba3ee986ab727fd0aff03812ff16
font_02_sfnt_off00010e99.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10E99 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1