Malicious PDF — malware analysis report

Static analysis result for SHA-256 897dd83ac4a51921…

MALICIOUS

PDF

69.5 KB Created: 2021-09-19 02:25:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 2fdca474ccd41f9fe1ab587c5f21034f SHA-1: 1c2a428f6a0bccde63151ace1025a25682f67a40 SHA-256: 897dd83ac4a51921c365dc631f82597e255aebbc111a08deff4abdffe9a1c512
164 Risk Score

Malware Insights

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

The sample is a PDF containing embedded JavaScript, which is a common technique for delivering malicious content. The PDF also hosts a link farm pointing to compromised WordPress sites, likely intended to trick users into downloading further malware. The ML classifier and ClamAV detection strongly indicate malicious intent, and the embedded JavaScript likely facilitates the download and execution of a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://pes.edu.mn/ckfinder/userfiles/files/nefoximejojulobofidi.pdf In PDF document text
    • https://brylka-kfz.de/wp-content/plugins/formcraft/file-upload/server/content/files/16134228396d7a---77375632660.pdfIn PDF document text
    • https://nsck-cykelmotion.dk/ckfinder/userfiles/files/563065191.pdfIn PDF document text
    • http://topflexsports.com/uploads/nukusezaxutasenitawikali.pdfIn PDF document text
    • http://www.nbrownies.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16140ed889d91a---zosowemotuj.pdfIn PDF document text
    • http://poptheme.cn/uploadfile/files/20210913_120323.pdfIn PDF document text
    • http://sahrugs.com/userfiles/file/83033259550.pdfIn PDF document text
    • http://caytrong.vn/Images_upload/files/sukijumov.pdfIn PDF document text
    • https://www.santaterezinha.com.br/js/ckfinder/userfiles/files/pizumepabesolofe.pdfIn PDF document text
    • https://too.kg/wp-content/plugins/super-forms/uploads/php/files/ba68dceeff3dadb665bc3eacf6847946/80650619183.pdfIn PDF document text
    • http://hillsclinic.com/fckeditor/editor/filemanager/connectors/php/userfiles/file/32360505342.pdfIn PDF document text
    • http://quaint-house.com/images/blog/file/4404289184.pdfIn PDF document text
    • http://www.festivalmarrakech.info/wp-content/plugins/formcraft/file-upload/server/content/files/1613cceeb17bd8---jijaxojagot.pdfIn PDF document text
    • http://www.kizkulesikizogrenciyurdu.com/public/ckfinderuploads/files/goziditadobizukatajedos.pdfIn PDF document text
    • http://krallarintavugu.com/upload/file/vefajudan.pdfIn PDF document text
    • http://akcihlar.cz/userfiles/file/87153552109.pdfIn PDF document text
    • http://wakingbeauty.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138f770cf247---foroforagazigot.pdfIn PDF document text
    • https://chiataiec.com/userfiles/Proj_Name/files/56790208638.pdfIn PDF document text
    • http://usmleworkout.com/files/file/babirejopunulukoba.pdfIn PDF document text
    • http://imcborivali.org/userfiles/file/xaraxewigubajubapijibak.pdfIn PDF document text
    • http://acetuitioncentre.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1614258d349918---71942361029.pdfIn PDF document text
    • http://fsoa.cn/userfiles/file/37514400842.pdfIn PDF document text
    • http://alpinedelhi.com/userfiles/files/31309978325.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/FevRqgeaUVY/uplcv?utm_term=little+nightmares+android+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_off0000b3fb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB3FB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cc12.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCC12 10736 bytes
SHA-256: 52c10bd6685a3e9d4b4476b145008100209edb6125182c2571feece49f897a70
font_02_sfnt_off0000e457.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE457 14248 bytes
SHA-256: fd206cc5d935d7be7d221c82b77d1053ac71a9820b99fdcbd3e13cfab0921156

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