Malicious PDF — malware analysis report

Static analysis result for SHA-256 35b4f1231500a0eb…

MALICIOUS

PDF

83.2 KB Created: 2021-07-14 04:35:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-14
MD5: dd1ef94ea825b159f7bb1f476874eabf SHA-1: 569be35f5268dbeeef0f9c37309b688ca3a9e9c9 SHA-256: 35b4f1231500a0eb41f6bafc4ea3d32dd6bdad230d335d2a4e52a827f1615a37
156 Risk Score

Malware Insights

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

The sample was identified as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics indicate the PDF functions as a link farm, with many URLs pointing to compromised CMS uploads and disposable hosting, suggesting an attempt to distribute further malicious content or phishing pages. The document body is heavily obfuscated and appears to be non-readable content generated by wkhtmltopdf, rather than user-facing text.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9833

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 http://hutbephottaihaiphong24h.com/upload/files/nuxewagijaretixumekari.pdf In PDF document text
    • http://ipvoicenj.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609c0bd3f116e---96872442383.pdfIn PDF document text
    • https://www.ikedatosou.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c17d4c5c554---gifem.pdfIn PDF document text
    • http://sampsonancestry.com/clients/d/d9/d9bd9208c4e45de01aa31840e3a8c66b/File/boxafofujinoxitogagugof.pdfIn PDF document text
    • http://www.nuricomuvakfi.org/wp-content/plugins/super-forms/uploads/php/files/2n00tk0t88qq6vhuhq1t0d5vd5/18139891571.pdfIn PDF document text
    • http://vinmexindia.com/uploads/tejewa.pdfIn PDF document text
    • https://www.kunapak.com/wp-content/plugins/super-forms/uploads/php/files/h725pffttla5f6743aj5vcmu0l/kimasomojuruwezipomev.pdfIn PDF document text
    • https://www.revistadefiesta.com/wp-content/plugins/formcraft/file-upload/server/content/files/16081ada91cf77---7174718245.pdfIn PDF document text
    • http://kirks-pool.com/wp-content/plugins/formcraft/file-upload/server/content/files/16090a2cd49ad5---fojewunumele.pdfIn PDF document text
    • https://morabia.fi/images/file/dorovemafunemikamasidu.pdfIn PDF document text
    • https://rffsev.ru/wp-content/plugins/super-forms/uploads/php/files/9a683da9b833fd8f428ef1d87faba592/44422041531.pdfIn PDF document text
    • https://www.ikedatosou.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d4e0e3b13a9---85557979040.pdfIn PDF document text
    • http://es-umzuege-transporte.de/wp-content/plugins/super-forms/uploads/php/files/82569dbaec4eee8aeca1f7269f08abc2/wexedisudobopalakude.pdfIn PDF document text
    • http://aelma.com/sites/default/userfiles/file/54832280024.pdfIn PDF document text
    • https://limpjet.com.br/wp-content/plugins/super-forms/uploads/php/files/63b889f6c1955fa3bd663acf2e328fd6/nesuminetatekop.pdfIn PDF document text
    • http://mirandatutoringcentre.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1607cb82ebcc83---botowujolegafovubeti.pdfIn PDF document text
    • https://www.helpforbusymums.com/wp-content/plugins/super-forms/uploads/php/files/f0350a89baa8ea857e6ba4c75582df84/kisap.pdfIn PDF document text
    • https://mandalaconfeccao.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160855a66ae468---91529349427.pdfIn PDF document text
    • http://www.ncstarim.com.tr/wp-content/plugins/super-forms/uploads/php/files/qe7p7ni8m390kkah8v7lnj9n90/87571574837.pdfIn PDF document text
    • https://c4ir.ae/wp-content/plugins/super-forms/uploads/php/files/qdol5e0icbsbom7vcki5do5b74/26293021853.pdfIn PDF document text
    • http://rogo-rotterdam.nl/files/76706637913.pdfIn PDF document text
    • http://rafaelstore.ru/upload/files/fanuriwuponovewupujo.pdfIn PDF document text
    • https://ahha.az/userfiles/file/sofizibebotu.pdfIn PDF document text
    • https://schreinerheusi.de/wp-content/plugins/formcraft/file-upload/server/content/files/16084bb51cd01b---balafukivumez.pdfIn PDF document text
    • http://consulcongress.it/uploads/assets/file/wosufenibobegofoxifixenu.pdfIn PDF document text
    • http://xperion.hu/wp-content/plugins/super-forms/uploads/php/files/ea059ce433f6344b421e1f997940ce92/95085038919.pdfIn PDF document text
    • http://www.realisthotel.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ab7b478d58d---navozuliwijagumo.pdfIn PDF document text
    • http://www.mywil.ch/wp-content/plugins/formcraft/file-upload/server/content/files/160a29188ab5e8---16107537628.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/A3Ryygt5BCM/uplcv?utm_term=x+force+2014+downloadPDF 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_off0000e018.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE018 18564 bytes
SHA-256: 5885c9a61ccf6884f6d9b44a450ad17def811b333c361ae863b230f9e36dec39
font_01_sfnt_off00010efa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10EFA 10576 bytes
SHA-256: 65722766c7f8b4b40aec8b870b07195f15af949989a05b8834d78daf13dbc7fd
font_02_sfnt_off0001276d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1276D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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