Malicious PDF — malware analysis report

Static analysis result for SHA-256 b237c957b16031e1…

MALICIOUS

PDF

82.0 KB Created: 2021-09-19 00:36:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 448d8eab5b91c2d5b07c9fbd226dd528 SHA-1: d4640ecd3ffca853ed6c3f335a28742d95629b82 SHA-256: b237c957b16031e1c6c6a4cdbc5c1cc12e6aec790f6b8b65c686446bddda9b94
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically identified as a phishing trojan. Heuristics indicate it functions as a link farm, with many URLs pointing to compromised WordPress sites and potentially disposable hosting. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://synerhu.ru/uplcv?utm_term=nintendo+3ds+games+roms PDF link annotation
    • http://uniondeautoescuelas.com/wp-content/plugins/formcraft/file-upload/server/content/files/16130047656c0b---pepotuzezawes.pdfIn PDF document text
    • https://atputasbazes.lv/images/userfiles/files/46460387091.pdfIn PDF document text
    • http://elcolono.net/userfiles/files/badiluxolalikepe.pdfIn PDF document text
    • https://aldurra.ly/images-editeur/img/file/giwepebexo.pdfIn PDF document text
    • http://sial.pl/galeria/file/dawinesise.pdfIn PDF document text
    • http://mylivediamondinventory.com/uploads/files/70692690820.pdfIn PDF document text
    • https://almentispharma.com/ckfinder/userfiles/files/86379109547.pdfIn PDF document text
    • http://glamour-nsk.ru/ckfinder/userfiles/files/lisepivonuzijosaginejif.pdfIn PDF document text
    • https://newdesert.pl/userfiles/file/9313747020.pdfIn PDF document text
    • http://www.mondzorgvesa-voorschoten.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1614154c62742c---gagetezejek.pdfIn PDF document text
    • https://rails-bg.com/fckeditorfiles/file/65422694670.pdfIn PDF document text
    • https://atlasautoglass.com/wp-content/plugins/formcraft/file-upload/server/content/files/161433e3cee6b7---30588161225.pdfIn PDF document text
    • http://escuelasfutbol8.com/docs/files/gopofu.pdfIn PDF document text
    • https://senzedigicraft.com/wp-content/plugins/super-forms/uploads/php/files/abfad2d69e094af7c80527314acd49f8/20958594578.pdfIn PDF document text
    • http://ttlengenharia.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1613c46f6dd324---desirebatumaperekep.pdfIn PDF document text
    • http://milkexim.ru/imgeditor/file/vamudipifenigejuxaxa.pdfIn PDF document text
    • http://01host.ru/userfiles/files/3874206633.pdfIn PDF document text
    • https://www.opdrrustukalac.com/wp-content/plugins/formcraft/file-upload/server/content/files/161391f041cad2---lolivexexowalasakejomasax.pdfIn PDF document text
    • https://stancijanegrin.com/UserFiles/files/valevefixosi.pdfIn PDF document text
    • http://www.siposferenc.hu/html/38242378416.pdfIn PDF document text
    • http://sutipatika.hu/userfiles/files/81882819883.pdfIn PDF document text
    • https://www.willmarareachamber.com/ckfinder/userfiles/files/58644152985.pdfIn PDF document text
    • http://agisinfo.ru/uploads/content/files/47057769736.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_off0000dcb8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDCB8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f4ca.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF4CA 17500 bytes
SHA-256: 55695f41cc4a346ae0608e3a903e58806278ed56492d5a068f9eafba61668da5
font_02_sfnt_off000122a9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x122A9 10692 bytes
SHA-256: d815625942d07c7a39e7829a5fad44bd0d25a564c5997714e6115a1c2c657925

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