{
  "family": "seznam",
  "sample_count": 1,
  "category": "trojan",
  "description": "<h3>Executive Summary</h3>\nIn a cybersecurity context, \"Seznam\" detections typically refer to aggressive browser hijackers and Potentially Unwanted Programs (PUPs) that forcefully alter a user's web browser settings to redirect traffic to the legitimate Czech search engine, Seznam.cz. While Seznam itself is a legitimate company, unscrupulous third-party affiliates utilize malicious software wrappers (adware) to force users to use the engine, thereby generating fraudulent affiliate revenue for the malware distributors.\n\n<h3>Infection Vector and Technical Capabilities</h3>\nThe Seznam-hijacking adware is primarily distributed via deceptive software bundling. Users encounter it when downloading \"freeware\" or pirated software from third-party aggregators. The installation process uses \"Dark Patterns\" to hide the fact that the browser settings are being modified.\n\nOnce installed, the adware exhibits classic hijacking behaviors:\n<ul>\n<li><strong>Homepage and Search Engine Modification:</strong> It aggressively alters the default homepage, new tab page, and default search engine in Chrome, Firefox, and Edge, hardcoding them to redirect to specific affiliate URLs associated with Seznam.</li>\n<li><strong>Extension Installation:</strong> It often installs a browser extension to ensure persistence. If the user attempts to manually change their search engine back to Google or Bing, the extension instantly reverts the settings upon the next browser launch.</li>\n<li><strong>Registry Locking:</strong> Advanced variants modify Windows Registry keys (or utilize Group Policy Objects) to lock the browser settings, preventing non-administrative users from making changes to their browser preferences.</li>\n</ul>\n\n<h3>Threat Assessment</h3>\nWhile not destructive like a Trojan, this form of adware is highly disruptive. It causes significant frustration for the user, degrades browsing performance, and often tracks search queries for marketing purposes. The persistence mechanisms cause unnecessary overhead for IT helpdesks attempting to clean the endpoint.\n\n<h3>Incident Response and Remediation</h3>\n<ul>\n<li><strong>Manual Uninstallation:</strong> IT staff should first check the Windows \"Add/Remove Programs\" list for any recently installed suspicious toolbars or \"Search Protect\" applications and uninstall them.</li>\n<li><strong>Anti-Malware Scan:</strong> Run a comprehensive scan using an enterprise anti-malware solution specifically configured to detect and remove PUPs and Adware registry keys.</li>\n<li><strong>Browser Factory Reset:</strong> To completely eradicate the hijacking components and persistent extensions, all installed web browsers must undergo a full factory reset to purge the malicious settings.</li>\n</ul>",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [
    "Adware.Seznam",
    "BrowserHijacker.Seznam",
    "PUP.SeznamToolbar"
  ],
  "enrichment_level": "insufficient_information",
  "faq": [],
  "faq_count": 0,
  "mitre_attack": [
    "T1185",
    "T1562.001"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-07-02T07:18:19Z",
  "type": "Adware / PUP",
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ]
}