Malicious PDF — malware analysis report

Static analysis result for SHA-256 c5c91e3376497923…

MALICIOUS

PDF

72.0 KB Created: 2021-09-21 14:19:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 39f61a4f55e93b324ab3fd7c41447cf9 SHA-1: be588ddb81bf373e520337111b73c627eb26f182 SHA-256: c5c91e3376497923e836999d71dc9283f74e0b0a6ff267d8f5abfb7c0b2890fe
136 Risk Score

Malware Insights

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

The PDF document contains numerous links, many pointing to compromised WordPress sites and disposable hosting, suggesting a link farm designed to distribute malicious content. The 'SE_BROWSER_INSTALL_LURE' heuristic indicates the document's content likely directs users to install fake browser updates or extensions. While no scripts were directly extracted, the nature of the links and the lure heuristic strongly suggest the PDF is a delivery mechanism for further malicious activity, potentially involving JavaScript execution or exploitation.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

Heuristics 6

  • Browser extension / update installation lure high SE_BROWSER_INSTALL_LURE
    Document tells the user to install a browser extension, plugin, viewer, or browser update to view content — a common social-engineering path for credential theft and malware installation
  • 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=how+to+enable+notification+access+on+android+go PDF link annotation
    • http://ap116.ru/userfiles/file/87479855198.pdfIn PDF document text
    • https://kiptep.ru/file/likifuzimejunemokemipuz.pdfIn PDF document text
    • http://mastrodibaglio.it/userfiles/files/pugezavagur.pdfIn PDF document text
    • http://classicalgardenornaments.com/uplds/file/10526465481.pdfIn PDF document text
    • http://neo-net.info/giganet/files/file/27283700751.pdfIn PDF document text
    • https://pharma-tools.pl/galeria/file/gisikidivojulawo.pdfIn PDF document text
    • http://daithanhnam.com/upload/files/sofekolipaxidib.pdfIn PDF document text
    • http://ascensionchina.com/userfiles/file/sivididujogusativigevu.pdfIn PDF document text
    • https://www.uniqueartzz.com/wp-content/plugins/super-forms/uploads/php/files/l23b1ust2gf1h1drpjom9b1uhs/9938172211.pdfIn PDF document text
    • https://baxsporthorses.com/userfiles/file/29237924404.pdfIn PDF document text
    • http://aviafond.ru/userfiles/file/80651094941.pdfIn PDF document text
    • http://www.ccengis.be/applications/ckeditor/addons/ckeditor/ckfinder/userfiles/files/jenuradugudasawu.pdfIn PDF document text
    • https://speculatio.in/userfiles/file/guxitazanibawomu.pdfIn PDF document text
    • http://reclaimsplus.com/wp-content/plugins/super-forms/uploads/php/files/aeac019adab79126846057449dfcc12a/sisumubusi.pdfIn PDF document text
    • http://dajuicebarus.com/uploads/files/24138029278.pdfIn PDF document text
    • http://metalzilembo.it/userfiles/files/63332049326.pdfIn PDF document text
    • http://creativeindustries.ru/uploads/userfiles/file/bozasosabano.pdfIn PDF document text
    • https://www.opdrrustukalac.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f9b2828cd9---mozig.pdfIn PDF document text
    • http://peter-crooks.com/userfiles/file/bakepiwixedizukadolo.pdfIn PDF document text
    • http://greddy.com/admin/common/ckfinder/userfiles/File/95455317000.pdfIn PDF document text
    • http://humanlitech.com/files/files/71205436800.pdfIn PDF document text
    • https://combrooncom.com/contents/files/69185591298.pdfIn PDF document text
    • https://thefertilizergranulators.com/d/files/20156706653.pdfIn PDF document text
    • http://carsonpokebar.com/uploads/files/wegetulamutamobax.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_off0000b739.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB739 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cf4b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCF4B 16244 bytes
SHA-256: 2e93f951880e5b979a0abd8a4be842c74dc39ba285ce52fbee059f6cc7a3a173
font_02_sfnt_off0000f8f9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF8F9 10868 bytes
SHA-256: f77682d6c378422a0b559896ce320d17c578c4d8e529e8a037dc86d3f9d101f4