Malicious PDF — malware analysis report

Static analysis result for SHA-256 c551d3a51654492d…

MALICIOUS

PDF

99.5 KB Created: 2021-07-18 11:06:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 56f0110a22734e8fc0a63507c09c8d7f SHA-1: 68aaeaac7b8d48dc0bf6d95c23c54fccd32d33a5 SHA-256: c551d3a51654492d472767d446d382d11e9811a446f605685f7e73b345d8322d
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised CMS upload directories, indicating a link farm designed to redirect users to potentially malicious content. The ML classifier and ClamAV detection strongly suggest a phishing or trojan payload delivery mechanism. No scripts were extracted, and the document body was unreadable, but the URL structure and heuristic firings are sufficient to infer malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9936

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://agrotehholding.ru/wp-content/plugins/super-forms/uploads/php/files/7d042f1c84fe75bc5898bc50a2d47777/15110186440.pdf
    • http://www.191seo.com/wp-content/plugins/formcraft/file-upload/server/content/files/16099e7764fad5---muvilulamuvokuwada.pdf
    • https://homini.eu/wp-content/plugins/formcraft/file-upload/server/content/files/16075f249a719b---76723721791.pdf
    • https://weinquartier.at/wp-content/plugins/super-forms/uploads/php/files/4b5147aa9825f1fb02a5a9556bfdecad/famef.pdf
    • http://moveisgarciadigital.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160bf47c17e6a6---87083910597.pdf
    • http://imssp.by/data/images/fxeditor/file/zatidadimutupujijozen.pdf
    • https://forex-robo.org/wp-content/plugins/super-forms/uploads/php/files/5384b0ae8580c8bd388f1f1a696b0372/49818940642.pdf
    • http://sns.hu/_user/file/rogoboxe.pdf
    • https://edubox.mn/uploads/users/0/files/69484584539.pdf
    • http://vanillasky-ch.com/images/files/43295473692.pdf
    • http://thevelascofamily.com/clients/11614/File/femezupaku.pdf
    • http://www.hollyskauaicondo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608f8be7ebdf9---681120331.pdf
    • http://maslag.eu/userfiles/file/regijidaromawa.pdf
    • http://franklcalabreseattorney.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/lagebumunabufejojizonij.pdf
    • http://xycrusher.com/d/files/40138394024.pdf
    • http://vladjurnalist.ru/archive/file/20879548691.pdf
    • https://qualitycountscleaning.com/wp-content/plugins/super-forms/uploads/php/files/b0f140039f5eadb8ddf71e535df9d366/43073200285.pdf
    • https://anzmrrn.org/wp-content/plugins/formcraft/file-upload/server/content/files/1607ce09d6078e---tomivugizoradili.pdf
    • https://mandalaconfeccao.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16081417673ccc---27336165571.pdf
    • https://editionsitaliques.com/userfiles/file/18970876229.pdf
    • http://sinproval.it/userfiles/files/fatitevebukijam.pdf
    • https://skinrepublic.vn/webroot/img/files/zavires.pdf
    • http://businessvaluationapp.com//fck_files/file/19823240477.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/ngfLrbzwjls/uplcv?utm_term=romantic+themed+hotels+near+me
    • 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_off00012461.bin
a80c52904d955c611c600b76ff5505058772395e31ff5bebb1c85fcd53d0bfde
pdf-font-stream PDF embedded font (sfnt) at offset 0x12461 17060 bytes
font_01_sfnt_off0001507e.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x1507E 16792 bytes
font_02_sfnt_off00016895.bin
bc05c694d3630fa2bc21d7a26d8634c98818433615faf2aca240ea26cbf27fc2
pdf-font-stream PDF embedded font (sfnt) at offset 0x16895 10680 bytes