Malicious PDF — malware analysis report

Static analysis result for SHA-256 537bb8ae42d6532b…

MALICIOUS

PDF

81.2 KB Created: 2021-07-09 22:52:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 8505f954ffd965f178eaddb96ba2ac42 SHA-1: bcbaafbeed481ca9dab994852a407aa9c1fdfb8e SHA-256: 537bb8ae42d6532bba3ac8eeaa501b99f49326e2eb9823f298a66b078fd97605
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was flagged as malicious by multiple heuristics and a machine learning classifier. It contains numerous external URIs and links to compromised WordPress sites, suggesting it is part of a link farm designed to redirect users to malicious content. The presence of PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics indicates a sophisticated attempt to obscure the true destination and leverage compromised infrastructure. The primary attack pattern appears to be luring users to external sites, likely for phishing or to download further malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9949

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://cructi.ru/uplcv?utm_term=best+funny+names
    • http://www.css-jp.com/upfile/files/2021/06/20/25069669220.pdf
    • http://iideree.org/wp-content/plugins/formcraft/file-upload/server/content/files/160ca1dc446a53---fafamapuwofi.pdf
    • https://ludifrance.fr/userfiles/file/81482740599.pdf
    • https://www.duffylighting.com/wp-content/plugins/super-forms/uploads/php/files/c0e3773e8722acb907a6b10e50d8651a/tagifemiredarugisoxera.pdf
    • http://wakingbeauty.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a6fcef2c455---9113084152.pdf
    • https://gulertrafik.com/wp-content/plugins/super-forms/uploads/php/files/jcleppt99lc6m4kg6kgj8sspe8/36896784800.pdf
    • http://sazjah.com/wp-content/plugins/formcraft/file-upload/server/content/files/16078d61297073---2136284965.pdf
    • http://axiomestates.com/userfiles/file/59333841917.pdf
    • https://hmanagement.net/userfiles/file/xudilewinuleralojamigaluj.pdf
    • https://pacie.vn/web/uploads/files/64359433043.pdf
    • http://for-rent-antwerp.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a745fa3289b---dawejanu.pdf
    • https://kisikana.hr/userfiles/file/fomafotola.pdf
    • https://g3az.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607508e42063f---nigetazodufivut.pdf
    • https://nhaban24h.com.vn/wp-content/plugins/super-forms/uploads/php/files/9ffpb3se6itjmr9s67l9jjdjad/duradagaxuxofelatotoguve.pdf
    • http://www.liveartsaskatchewan.com/wp-content/plugins/formcraft/file-upload/server/content/files/160cbb99aa1aad---55623402478.pdf
    • http://www.iycadana.org/wp-content/plugins/super-forms/uploads/php/files/abu2lvev3ct1jn9fvegntu96k0/19340392506.pdf
    • http://szkolaprzybranowo.pl/ckfinder/userfiles/files/divuwobedeba.pdf
    • https://avantkart.com/wp-content/plugins/super-forms/uploads/php/files/k611buvd3htqhisn6tklc21tq2/fumofijize.pdf
    • http://phunggia.biz/userfiles/file/vatupimobevijivuji.pdf
    • http://www.veronicaneal.com/wp-content/plugins/formcraft/file-upload/server/content/files/1/160a5af0422968---fikozo.pdf
    • https://shining4u.com/wp-content/plugins/super-forms/uploads/php/files/01d660ab79ea600f124f70367078a913/vomomunaxowipafepazerot.pdf
    • https://www.coconutlodge.com/wp-content/plugins/formcraft/file-upload/server/content/files/16077e7c791fbd---82414476639.pdf
    • http://udclassof1968.com/clients/74076/File/xaralu.pdf
    • https://www.penyembuhanholistikreiki.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c51e85b525e---65039283748.pdf
    • http://nedirajtebosnu.net/userfiles/file/futovutik.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_off0000dd21.bin
eef2ba9dd5711e20c2b5efffa1885622d0208dca963ecddd70aff60ba9512856
pdf-font-stream PDF embedded font (sfnt) at offset 0xDD21 16744 bytes
font_01_sfnt_off00010897.bin
816e514786406dcc4e00b450c1c075e128bd6d79a750504dc68291413e12f861
pdf-font-stream PDF embedded font (sfnt) at offset 0x10897 10284 bytes
font_02_sfnt_off00011fd1.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x11FD1 16792 bytes