Malicious PDF — malware analysis report

Static analysis result for SHA-256 57d71cfabc7e5938…

MALICIOUS

PDF

86.3 KB Created: 2021-07-13 22:55:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 65082797646d37987123e0cc2b65361b SHA-1: fee0a7d80cbf0569e58b5b218daf04e351b77987 SHA-256: 57d71cfabc7e593818ef60bd9669e65fa5d7f724d69499ef8f82595d9afa02c3
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a large number of links, many pointing to compromised CMS upload directories, indicating a link farm designed to redirect users to malicious sites. The ML classifier strongly flagged this PDF as malicious. While no scripts were explicitly extracted, the nature of the links suggests potential for further exploitation or phishing attempts upon user interaction.

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 https://synerhu.ru/uplcv?utm_term=what+is+the+best+kind+of+exercise
    • http://www.ambredore.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a3d2dab79d0---67065346701.pdf
    • http://www.kissdocs.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1607693ff64982---86739659070.pdf
    • https://cms.blauraum.com/wp-content/plugins/super-forms/uploads/php/files/219e7fa2b43476a5c7aa9663f34392f6/94870729426.pdf
    • https://vieclamxaydung24h.com/upload/files/17760651229.pdf
    • https://aimara-bg.com/userfiles/file/vemokibuni.pdf
    • http://www.electricman.in/demo/frontend/web/uploads/files/sugakoxowerigonitopi.pdf
    • http://www.suffaheducation.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607e08e39298c---bipadabeta.pdf
    • http://www.veronicaneal.com/wp-content/plugins/formcraft/file-upload/server/content/files/1/1607c3803da9af---fimabaxuvitegadago.pdf
    • https://vidolamerica.org/wp-content/plugins/super-forms/uploads/php/files/57bae31967dace7b5983686562890a37/vofinazaxixivigakiwu.pdf
    • http://www.a-fairys-choice.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608f285821b5f---70901591514.pdf
    • https://mediabandit.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a2a03558cee---14753199220.pdf
    • https://guapa2.com/admin/fck/file/6877308788.pdf
    • http://twfbs.com/ckfinder/userfiles/files/98949852536.pdf
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607ba2e5cc73b---jakivep.pdf
    • http://parkwestresidences.com/wp-content/plugins/formcraft/file-upload/server/content/files/160cb6da49d304---3499653677.pdf
    • http://www.etoiles-recrutement.com/wp-content/plugins/formcraft/file-upload/server/content/files/160719b60049c2---95322688348.pdf
    • https://www.potterycommercials.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1607447863932f---mupalelul.pdf
    • https://sitebyside.ru/wp-content/plugins/super-forms/uploads/php/files/a6851e97a1d091c856d9a1c581504731/bobexuka.pdf
    • http://www.191seo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606cb4ac02c98---54073518268.pdf
    • http://cupta.org/userfiles/files/20210713212714.pdf
    • http://newmob.it/userfiles/files/78808137838.pdf
    • https://pypconsultores.mx/userfiles/file/42162119964.pdf
    • http://nowator-zpu.pl/userfiles/file/84939381200.pdf
    • http://irinaburmistrova.ru/files/24281748777.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000eb41.bin
fea93d4b1f12f4e4fa28ecb8fa77c801b240f11e909456dc4988e16a33de5692
pdf-font-stream PDF embedded font (sfnt) at offset 0xEB41 18352 bytes
font_01_sfnt_off00011ab3.bin
9d8e4762309179a99c3ea13747dad0918d6b4acd86278acd3bba9098c193b08d
pdf-font-stream PDF embedded font (sfnt) at offset 0x11AB3 10856 bytes
font_02_sfnt_off000133c6.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x133C6 16792 bytes