Malicious PDF — malware analysis report

Static analysis result for SHA-256 631738ee948e4751…

MALICIOUS

PDF

71.3 KB Created: 2021-09-20 14:01:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 1c388d1a03b9c709366d2ce9965036b4 SHA-1: 65cc1536d7b4155352678ed415f4dd3d30687447 SHA-256: 631738ee948e47517e441c4e2d446ad077752f5dd7475ea8fd3ce1ac9de7ab21
96 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, suggesting a tactic to host malicious content or redirect users. The ML classifier strongly flagged this PDF as malicious, and the presence of link farms on disposable hosting further supports a malicious intent. No scripts were extracted from this sample.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

Heuristics 5

  • 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://pistant.ru/uplcv?utm_term=one+piece+episode+951+online PDF link annotation
    • https://vcvscr.cz/www/www/fckphotos/file/92952220066.pdfIn PDF document text
    • https://t4g.nasscomfoundation.org/wp-content/plugins/super-forms/uploads/php/files/f63sd19ik56l6lq9rgv4akas25/16074243338.pdfIn PDF document text
    • https://www.costaverde.it/wp-content/plugins/formcraft/file-upload/server/content/files/1613938238003c---25713121266.pdfIn PDF document text
    • http://nineslash.com/user_file/file/kuvebisapuv.pdfIn PDF document text
    • http://lisahyatthealth.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614837fc31f3d---mosumexopupibufejom.pdfIn PDF document text
    • http://thomas-zigon.de/images/file/29639686240.pdfIn PDF document text
    • http://obrienbuilders.com/userfiles/file/niwomipofibiwesaxurelowi.pdfIn PDF document text
    • http://crm333.com/documentos/file/46938672018.pdfIn PDF document text
    • http://ebsenglish.net/_UploadFile/Images/file/61362014777.pdfIn PDF document text
    • http://studiofapas.it/userfiles/files/zaxadirujukefegomiso.pdfIn PDF document text
    • http://aloisiquadri.it/userfiles/files/ximerajewinajijamebodarem.pdfIn PDF document text
    • https://twr1115.net/files/fckeditor/file/wonadaxop.pdfIn PDF document text
    • http://618tuan.com/uploadfile/file/14786832805.pdfIn PDF document text
    • http://svatba-emi.com/uploads/pages/files/99219697848.pdfIn PDF document text
    • https://holcom-wd.com/webroot/img/files/sixuvupagijegaforonu.pdfIn PDF document text
    • https://rrvchefs.com/wp-content/plugins/super-forms/uploads/php/files/15dae0f09a1e58a9156919475f52549d/91947786624.pdfIn PDF document text
    • https://mongolia-volkslift.com/uploads/files/kisefap.pdfIn PDF document text
    • http://maybomnuocdanang.com/uploads/image/files/49659566884.pdfIn PDF document text
    • https://vialivonica.eu/userfiles/files/87529576441.pdfIn PDF document text
    • https://www.piramideidiomas.com/ckfinder/userfiles/files/zapizininot.pdfIn PDF document text
    • https://bilbox.es/wp-content/plugins/super-forms/uploads/php/files/022337bfa95c728bca8590c0b454f5eb/41240713233.pdfIn PDF document text
    • https://maribon.net/app/webroot/files/userfiles/files/pafafikutesanuzorug.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_off0000b3b7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB3B7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cbce.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCBCE 10524 bytes
SHA-256: 05f4755cb8c0ce869ad3dce1b4b856c942f5dc8c1b45301db4cde0cf14d55dca
font_02_sfnt_off0000e3e9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE3E9 16980 bytes
SHA-256: b46eb9ce1f03b92bdfbca83b372457a91db54c48df725b5a338313b666e7cd11