title: Katz Stealer Suspicious User-Agent id: 834c6d2f-5e98-4b2a-b453-0c4f234afedd status: experimental description: | Detects network connections with a suspicious user-agent string containing "katz-ontop", which may indicate Katz Stealer activity. references: - Internal Research author: Swachchhanda Shrawan Poudel (Nextron Systems) date: 2025-05-22 tags: - attack.command-and-control - attack.t1071.001 - detection.emerging-threats logsource: product: zeek service: http detection: selection: user_agent|contains: 'katz-ontop' condition: selection falsepositives: - Unlikely level: high