Malicious PDF — malware analysis report

Static analysis result for SHA-256 9951b4a1791f0a5e…

MALICIOUS

PDF

80.3 KB Created: 2021-09-20 09:43:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: f0e42d76b3b7911460c296bff7eacabc SHA-1: 98ac0da548f26468017b53cd572115959d3e58ea SHA-256: 9951b4a1791f0a5ea72776e7b79d0a8b23f3ef3afd514ca47fa1be04c50d1fff
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a large number of embedded URLs, many of which point to compromised WordPress sites or disposable domains. The ML classifier strongly indicated maliciousness, and the heuristic firings suggest this PDF is part of a link farm designed to manipulate search engine results or distribute malicious content. No scripts were extracted, and the document body was unreadable, limiting further analysis of the specific lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://inwebjor.ru/uplcv?utm_term=spotify+android+sleep+timer PDF link annotation
    • https://pcparts.fr/ckfinder/userfiles/files/70860563157.pdfIn PDF document text
    • https://oncallanatomist.com/ckfinder/userfiles/files/lidelirijituwivesubo.pdfIn PDF document text
    • https://dpt-mh.com/uploads/news/files/mutinenadili.pdfIn PDF document text
    • http://sushi-belovo.ru/files/wazuw.pdfIn PDF document text
    • http://tobn56.com/UpFiles/file/rilejozoxaxete.pdfIn PDF document text
    • http://sedaciesupravy.sk/media/file/6859000112.pdfIn PDF document text
    • https://massagetheory.ca/wp-content/plugins/super-forms/uploads/php/files/69cd582c88ec8bdebd18f6783098044f/tivovomaradimi.pdfIn PDF document text
    • http://dioceseofniranam.org/userfiles/file/tapomavaxi.pdfIn PDF document text
    • https://www.bouwenaaneensterkwerkgeversmerk.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1614141c6906a4---raxikes.pdfIn PDF document text
    • https://ncvpte.in/userfiles/file/61454636273.pdfIn PDF document text
    • http://ajk-opakowania.eu/upload/fck/file/55660498148.pdfIn PDF document text
    • https://oazapiekna.com/zdjecia/fck/file/43436185252.pdfIn PDF document text
    • http://tuclubcr.com/campannas/file/wobilatetedujibezezam.pdfIn PDF document text
    • http://copy-office.it/userfiles/file/tojubuxowidadodavi.pdfIn PDF document text
    • http://espokebar.com/uploads/files/magezujetisidigemeko.pdfIn PDF document text
    • https://www.budgetskemaet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/1613f4fbe20f9b---63303024112.pdfIn PDF document text
    • http://www.emporiocaritaspisa.it/wordpress/wp-content/plugins/formcraft/file-upload/server/content/files/16139e3a584e7b---jogowukiweworidepinuwex.pdfIn PDF document text
    • http://vasilii-orlov.fun/wp-content/plugins/super-forms/uploads/php/files/93bdcaf827949722cac3a8fa32f732b8/pinunotegikaxekaga.pdfIn PDF document text
    • http://bonezi.morefriendship.com/upload/files/fafadipadom.pdfIn PDF document text
    • https://centaur.vri.cz/docs/files/25291325780.pdfIn PDF document text
    • http://sententtech.com/file_media/file_image/file/85643152495.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_off0000d4f1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD4F1 18004 bytes
SHA-256: 067cacf9ade9ab770cdfd2b669d153870e063c02412a679d0a2a0177ac278783
font_01_sfnt_off00010323.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10323 10848 bytes
SHA-256: e17ecb89377a8ed776d871b69fce0eb15a6d60ae8f6ef0073353f3a599c90574
font_02_sfnt_off00011c30.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11C30 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1