Malicious PDF — malware analysis report

Static analysis result for SHA-256 12904c37e720c578…

MALICIOUS

PDF

74.2 KB Created: 2021-11-13 16:44:15 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: d8624a431f30eb086fbba8c47d99f7f5 SHA-1: 1378bd96f823403c233e18c7a27be91c3e96f4b7 SHA-256: 12904c37e720c57809b423aa83de9bead486b5afc472ef9ea0552ee02bda86e6
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised CMS upload directories or are part of a link farm on disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution through these links. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing content but serving as a vessel for the malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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://infrive.ru/uplcv?utm_term=best+pdf+to+text+converter+free PDF link annotation
    • https://www.aledrukujemy.pl/ckfinder/userfiles/files/94791996963.pdfIn PDF document text
    • http://youth-myth.com/userfiles/file/12488325914.pdfIn PDF document text
    • https://invest.pl/userfiles/file/ganoz.pdfIn PDF document text
    • https://libertyrealestate.in/ckfinder/userfiles/files/gububexij.pdfIn PDF document text
    • http://ambiance-cinema.fr/wp-content/plugins/super-forms/uploads/php/files/16d737e6102ffdd5dcc2c4413c657d5d/lotobos.pdfIn PDF document text
    • https://oolong-dining-co.com/webroot/editor-uploads/files/wonazakiwepabogego.pdfIn PDF document text
    • http://star-transform-moscow.ru/uimg/files/43205011160.pdfIn PDF document text
    • https://jamurgoreng.net/contents/files/11691975006.pdfIn PDF document text
    • http://immobiliareborghi.com/userfiles/files/95342389337.pdfIn PDF document text
    • http://xn--or3bo5mvlb.com/data/editor/file/navalazu.pdfIn PDF document text
    • http://www.ambatownship.com/ckfinder/userfiles/files/lokiwuvifidurapamukutevo.pdfIn PDF document text
    • http://cameradungphat.com/uploads/files/wunipotutivivebufe.pdfIn PDF document text
    • https://www.cukoyem.com.tr/wp-content/plugins/super-forms/uploads/php/files/15939gql21g0qa015uub9njfb4/disetokubazajuj.pdfIn PDF document text
    • http://drvision.org/wp-content/plugins/formcraft/file-upload/server/content/files/161742173107b8---86777810957.pdfIn PDF document text
    • http://uni-soar.com/userfiles/file/geduwupatiledulugebad.pdfIn PDF document text
    • http://energo-winstal.pl/userfiles/file/senuwadozi.pdfIn PDF document text
    • http://op-gold.com/ck_image/files/62147455214.pdfIn PDF document text
    • http://www.icodar.com/wp-content/plugins/formcraft/file-upload/server/content/files/16140e3f9bc9b6---xinoxapikoxelukizit.pdfIn PDF document text
    • https://jaunimodienos.lt/wp-content/plugins/super-forms/uploads/php/files/kdae605ctcfgds7famo66is15n/4812819109.pdfIn PDF document text
    • https://padservhosting.com/userfiles/file/ribuvakuxodo.pdfIn PDF document text
    • https://journeywithmypet.com/ckfinder/userfiles/files/tamanela.pdfIn PDF document text
    • http://seyrimerdin.com/userfiles/file/12101920551.pdfIn PDF document text
    • https://mobspace.xyz/web/img/podborky/files/53847193171.pdfIn PDF document text
    • http://wksx.top/images/userfiles/file/lerojamutixeleluzalatem.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_off0000bd9e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBD9E 16540 bytes
SHA-256: 45015263e28dbf00792e0fa83ae0fb9123af5110209f191c00797c49350166ef
font_01_sfnt_off0000d4c4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD4C4 10532 bytes
SHA-256: eaccea66e021ebdca8ee7c2ca0d65ca96f1b16e51490ebfab59adeeda1fba6ea
font_02_sfnt_off0000ecf4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xECF4 17516 bytes
SHA-256: 2e936b27c6f2bacd8d5fd65c2e606fa5fb855f73b4091b1c748a044cc5472451

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