Cisco released a set of tool to investigate Cisco devices
https://tools.cisco.com/security/center/resources/iosxe_forensic_guide
https://tools.cisco.com/security/center/resources/ios_forensic_investigation
https://tools.cisco.com/security/center/resources/ftd_forensic_investigation
https://tools.cisco.com/security/center/resources/asa_forensic_investigation
https://tools.cisco.com/security/center/tacticalresources.x
https://tools.cisco.com/security/center/resources/asa_forensic_investigation
Digital Forensics Tool Catalog https://toolcatalog.nist.gov/search/index.php?ff_id=16