Malicious PDF — malware analysis report

Static analysis result for SHA-256 90057211c9f72e63…

MALICIOUS

PDF

70.4 KB Created: 2021-09-27 12:44:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: f66b8cfc878284c0669a635d56d9f6fe SHA-1: 1d971ac440a3ee5da65714e08d5ff1f1f8fab335 SHA-256: 90057211c9f72e634c171eb38f65574791d8f159e9989c33728873f7e70e6908
96 Risk Score

Malware Insights

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

The sample is a PDF document identified as malicious by an ML classifier. It contains a link farm with numerous URLs, several of which point to compromised WordPress upload directories. The document body is unreadable, but the heuristics indicate a non-clustered link farm on disposable hosting, suggesting an attempt to distribute malicious links or redirect users to harmful sites. The presence of multiple compromised CMS upload links further supports this malicious intent.

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 http://cargo3030.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1615169e6ef325---2339452563.pdf In PDF document text
    • http://castel.lu/userfiles/files/30682875991.pdfIn PDF document text
    • http://clubselectionvoyages.com/images/file/womuxolifetufibajuzij.pdfIn PDF document text
    • https://blsautomation.com/ckfinder/userfiles/files/butuvegebizafafumowax.pdfIn PDF document text
    • http://trivio.it/userfiles/files/sozezavuniri.pdfIn PDF document text
    • https://innotek.vn/uploads/news_file/mesolufa.pdfIn PDF document text
    • http://mrcubezpieczenia.pl/app/webroot/media/files/20561284860.pdfIn PDF document text
    • http://steffis-strassladen.de/userfiles/file/lotunopav.pdfIn PDF document text
    • https://zenmobile.in/jaipriyart/uploads/files/28444298700.pdfIn PDF document text
    • http://seyrimerdin.com/userfiles/file/pemufobexenoge.pdfIn PDF document text
    • http://plkorea77.com/ckupload/files/pozozuwimevenedofu.pdfIn PDF document text
    • https://vargyasnekonyveles.hu/kepek/other/file/mozunejupajo.pdfIn PDF document text
    • http://ecole.ru/text/images/file/33182094238.pdfIn PDF document text
    • http://taeguektour.com/FileData/ckfinder/files/20210911_342F391016938102.pdfIn PDF document text
    • https://hot-pol.com/images/file/50170569950.pdfIn PDF document text
    • https://mamproducciones.es/wp-content/plugins/formcraft/file-upload/server/content/files/1614030fe35f66---vabavudugukudofitezosezi.pdfIn PDF document text
    • http://medicalproduct.hu/images/files/95577094872.pdfIn PDF document text
    • http://gccde.com/downloads/blog/geust/files/vofalajoju.pdfIn PDF document text
    • http://www.fred-robin.com/ckfinder/userfiles/files/jivane.pdfIn PDF document text
    • https://kheops-so.fr/ckfinder/userfiles/files/94885096361.pdfIn PDF document text
    • http://mingzhicc.com/userfiles/files/39492288108.pdfIn PDF document text
    • https://kicksomeglass.com/wp-content/plugins/super-forms/uploads/php/files/b8db465a9ffbf2dabb6aeccb764198c8/58510108953.pdfIn PDF document text
    • http://szguilong.com/userfiles/files/6587204717.pdfIn PDF document text
    • https://mekongtransport.com/upload/userfiles/files/62497619456.pdfIn PDF document text
    • https://stonebuild.bg/f/uploads/files/19829310000.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/PmAiG5ZyT-k/uplcv?utm_term=8+letter+words+starting+with+uPDF 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_off0000b463.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB463 15208 bytes
SHA-256: 6e8f2e4fe11b959b03dff90f11e99b36f776b7df2284040342e5d2c347e976e6
font_01_sfnt_off0000dad7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDAD7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f2ee.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2EE 10824 bytes
SHA-256: 981b2a6c3ae21c8ad942a96d41b494261ceb4e3806751f8fcb2103dd24edd23b