With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
ceImageVersion
Cisco Enhanced Image Version
1.3.6.1.4.1.9.9.249.1.1.1.1.5
Version of the running OS image.
Back to CISCO-ENHANCED-IMAGE-MIB MIB page.
IPHost Network monitor allows you to monitor ceImageVersion on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco firewalls right now.