Malicious PDF — malware analysis report

Static analysis result for SHA-256 1890e87b250a5c11…

MALICIOUS

PDF

80.7 KB Created: 2021-10-09 01:32:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 24d162133b49214212cc419902143d26 SHA-1: 35b3c7dbb0c0570d20ab6e57d4c0d44f9beaf53b SHA-256: 1890e87b250a5c11929ff2fd07d656d14bf1cebe2d03d6d2f10eaa9778495ab6
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains a large number of embedded URLs, many of which point to PDF files hosted on various domains. Several heuristics indicate this is a link farm, with some links pointing to compromised CMS uploads. The ML classifier strongly suggests malicious intent. The primary purpose appears to be directing users to external, potentially malicious, PDF content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9968

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://ikincielinmak.com/upload/ckfinder/files/73582606374.pdf In PDF document text
    • http://tangneylaw.com/admin/images/file/fakenegix.pdfIn PDF document text
    • http://agecarekorea.com/ckupload/files/4566705001.pdfIn PDF document text
    • http://ntep2008.com/UserFiles/File/vekoni.pdfIn PDF document text
    • http://lempreintedubois.fr/userfiles/lempreintedubois.fr/file/22028802568.pdfIn PDF document text
    • https://obrbikes.com/files/files/25483421553.pdfIn PDF document text
    • http://merklink.nl/site/data/ws/files/35224961580.pdfIn PDF document text
    • https://orderpoet.com/ckfinder/userfiles/files/gifus.pdfIn PDF document text
    • http://quangcaosmsgiare.com/media/ftp/file/gudosokiguw.pdfIn PDF document text
    • http://ovartec.com/wp-content/plugins/formcraft/file-upload/server/content/files/16135d7067ea7f---mitaxujanigapikipixave.pdfIn PDF document text
    • http://landroverbh.com/ckfinder/userfiles/files/61458068704.pdfIn PDF document text
    • http://siblom.ru/files/upload/file/95580538703.pdfIn PDF document text
    • http://evaemlak.com/userfiles/file///36708720221.pdfIn PDF document text
    • https://soosekszer.hu/upload/files/waxotetex.pdfIn PDF document text
    • http://phamtrangia.com/upload/files/nadasutejixusud.pdfIn PDF document text
    • http://qcfloor.com/userfiles/file/disavanelukinedu.pdfIn PDF document text
    • http://testplanet.nl/uploads/files/lufaresigivokom.pdfIn PDF document text
    • http://viaterrestre.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1615ab1dd22f5f---6806780995.pdfIn PDF document text
    • https://serviceservice.eu/userfiles/file/43518089246.pdfIn PDF document text
    • https://kuwaitpolyurethane.com/ckfinder/userfiles/files/javidafafuwa.pdfIn PDF document text
    • https://ana-jsc.com/upload/files/geluxexulagixexojevop.pdfIn PDF document text
    • https://www.etbsupplies.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613eac860e558---tosazunezifawufu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BvfzZFkJO3s/uplcv?utm_term=divisibility+test+1+to+11PDF 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_off0000d4de.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD4DE 19064 bytes
SHA-256: fa921d72aba78cff8e6035640a77fefe13f86b5ca7c73bb355762762a6cc824b
font_01_sfnt_off000106de.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x106DE 10108 bytes
SHA-256: 05c56d240b94c912e1ff9e793a505f5b811fc1b510ee768ad16e6b9c35bd4193
font_02_sfnt_off00011da4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11DA4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1