Malicious PDF — malware analysis report

Static analysis result for SHA-256 935fdc1f2773b156…

MALICIOUS

PDF

90.6 KB Created: 2021-06-08 22:10:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-04
MD5: 1357acb919d0eb39ee79b2f6b306f0e9 SHA-1: bbbadda182a2eb9e159d3f98ddfde2ee8d32cd26 SHA-256: 935fdc1f2773b156360c60bf2d0b528560d86aaf0dccedabec0b075a483f3cda
136 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution T1059.007 JavaScript

This PDF document was flagged as malicious by an ML classifier. It uses a fake browser/software-install lure. The file embeds a large number of external links characteristic of an SEO link farm, many hosted on compromised CMS upload directories. Specific URLs and indicators for this sample are listed in the indicators section.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 6

  • Browser extension / update installation lure high SE_BROWSER_INSTALL_LURE
    Document tells the user to install a browser extension, plugin, viewer, or browser update to view content — a common social-engineering path for credential theft and malware installation
  • 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://crewmak.ru/uplcv?utm_term=how+to+get+answers+from+delta+math PDF link annotation
    • https://homini.eu/wp-content/plugins/formcraft/file-upload/server/content/files/160b851b534c9d---kavinawuzojuzugugelixalum.pdfIn PDF document text
    • https://xn--80adj7cxa.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/c6edd370de742c73523b823cee5149d6/gekigusol.pdfIn PDF document text
    • http://alimentosldm.com/userfiles/file/rudesatupotiru.pdfIn PDF document text
    • http://kirks-pool.com/wp-content/plugins/formcraft/file-upload/server/content/files/16091e14f7445f---zulenobuzuxu.pdfIn PDF document text
    • https://samiznojmo.cz/wp-content/plugins/super-forms/uploads/php/files/17b7299472fb7859d37beaa8b69aa4f6/supesumuvabagod.pdfIn PDF document text
    • http://www.nandomoraes.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160a38fb5385de---bemoxasuraze.pdfIn PDF document text
    • https://enville.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f28246e173---lokibozudowojononatewu.pdfIn PDF document text
    • http://perfectthesale.com/wp-content/plugins/formcraft/file-upload/server/content/files/160778fae80366---xokexokasifakalav.pdfIn PDF document text
    • http://elenasteele.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607b71760a138---60414559753.pdfIn PDF document text
    • http://lncxjzxxw.com/upload_fck/file/2021-6-8/20210608005311518931.pdfIn PDF document text
    • http://caacoding.net/wp-content/plugins/formcraft/file-upload/server/content/files/1607ced0fb67ec---63770806844.pdfIn PDF document text
    • http://andreaslasnik.com/data/files/rakobobetobok.pdfIn PDF document text
    • https://samyenngochoang.com/wp-content/plugins/super-forms/uploads/php/files/ngjthjs6b47fbgeai0jhqif7ma/59459904474.pdfIn PDF document text
    • https://bakwanudang.com/contents//files/29387113302.pdfIn PDF document text
    • https://capitalsyndic.com/userfiles/file/miluteguxotexitidin.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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://scripts.sil.org/OFLIn 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_off000109d1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x109D1 5376 bytes
SHA-256: f8f85d23b3e10785d27e75a1996eed50b6bb1de2afb5f9c63340eea543d74b13
font_01_sfnt_off00011bfc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11BFC 12368 bytes
SHA-256: db393cfddcdc9f217191d771515ba2637f6487b43eec2eced43caa82ec649d0b
font_02_sfnt_off00014686.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14686 16088 bytes
SHA-256: fff8b70d67420864e2a263fdbbaad35efae781e73a516d3cf38207748e8715b5