Malicious PDF — malware analysis report

Static analysis result for SHA-256 a3ec3159d92ff832…

MALICIOUS

PDF

88.6 KB Created: 2021-06-28 07:05:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 556c0f6587ae2f33d0b50e9145b05252 SHA-1: 30e674d9aba0042af88df58e1ca9c2fb36be786a SHA-256: a3ec3159d92ff8321ca4f8033aee2505b3d4013b4cbcf3f8cde4fae459d9b5f7
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file contains a link farm pointing to numerous compromised WordPress sites, which in turn host other PDF files. This suggests a tactic to manipulate search engine rankings or distribute malicious content through a chain of compromised resources. The ML classifier strongly indicated maliciousness, and the heuristic firings confirm the link farm behavior.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9947

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 http://wksystems.net/HotelEstimator/userfiles/file/92849946226.pdf In PDF document text
    • http://www.cascinasorigherio.it/wp-content/plugins/formcraft/file-upload/server/content/files/160bbd05712769---44047440699.pdfIn PDF document text
    • https://mandalaconfeccao.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160aa2b26e8ed1---19175021319.pdfIn PDF document text
    • http://esrafisek.com/images_upload/files/83260378967.pdfIn PDF document text
    • http://www.urbanwaterways.info/files/49865277163.pdfIn PDF document text
    • https://rffsev.ru/wp-content/plugins/super-forms/uploads/php/files/94c40dc302b5528a5e827056490803a1/857327332.pdfIn PDF document text
    • http://training-solutions.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1607ae3690765b---63877151033.pdfIn PDF document text
    • https://smarttactic.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160946db42d8bd---58724559847.pdfIn PDF document text
    • https://www.duffylighting.com/wp-content/plugins/super-forms/uploads/php/files/ca564e9c24d64cdfb0e95e87afd226a3/tafoxuxivizikaridol.pdfIn PDF document text
    • https://oiweld.com/wp-content/plugins/super-forms/uploads/php/files/5d751c9f31be888b7ec06e399613b7ab/62135060450.pdfIn PDF document text
    • http://www.rodnolespropertymanagement.com/siteuploads/editorimg/file/kalabekibasewuzerisaju.pdfIn PDF document text
    • http://ebsenglish.net/_UploadFile/Images/file/24947538881.pdfIn PDF document text
    • https://martybermanassociates.com/wp-content/plugins/super-forms/uploads/php/files/582b746a3c198e7d567012bfee7a1720/73545721320.pdfIn PDF document text
    • http://learningkey.org/userfiles/pojerag.pdfIn PDF document text
    • http://taxicityplus.ru/userfiles/file/73523008332.pdfIn PDF document text
    • https://plumcourse.com/wp-content/plugins/super-forms/uploads/php/files/7e260f0b0b6c6e432f5d8a2d2c1d6b41/vunapabugiliberawaduragam.pdfIn PDF document text
    • http://www.caslyn.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160c2b9bc3658a---33376031817.pdfIn PDF document text
    • https://zweiund40.com/wp-content/plugins/super-forms/uploads/php/files/44uuhkenb1iq89mlnog0177shp/32569364794.pdfIn PDF document text
    • http://urjabatteries.in/userfiles/file/gorixululi.pdfIn PDF document text
    • https://nobleanimalsanctuary.org/wp-content/plugins/super-forms/uploads/php/files/tmp/junijum.pdfIn PDF document text
    • http://www.wallisandemmanuel.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608c41ea67e71---62424525782.pdfIn PDF document text
    • https://sarujiovalente.com/wp-content/plugins/super-forms/uploads/php/files/7usg4lpjmoh7936ip4qgq1fqvt/fisis.pdfIn PDF document text
    • https://velvetskin.pl/wp-content/plugins/super-forms/uploads/php/files/5d3fa57401ba46bb289ee2c342a64a6d/vibaximidimeketilotuwir.pdfIn PDF document text
    • https://www.emma-solutions.de/wp-content/plugins/formcraft/file-upload/server/content/files/160b96cbb534ef---59399894715.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/FevRqgeaUVY/uplcv?utm_term=different+ways+to+say+friend+in+spanishPDF 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_off0000f684.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF684 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010e96.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10E96 18268 bytes
SHA-256: eb36a2a50580ce2ae2348f3c45a81c01f6693204b7bf01d85ae0a42bb6e3c09c
font_02_sfnt_off00013c41.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13C41 10748 bytes
SHA-256: 5a55e90070fca027b751ad09212a1ebd3d3b65cbc5d3cd1045e8c2ab5b6625e5