With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cHsrpGrpAuth
Cisco Hot Standby Router Protocol Group Authentication
1.3.6.1.4.1.9.9.106.1.2.1.1.2
This is an unencrypted authentication string which is carried in all HSRP messages. An authentication string mismatch prevents a router interface from learning the designated IP address or HSRP timer values from other HSRP-enabled routers with the same group number. The function of this object is not to supply any sort of security-like authentication but rather to confirm that what's happening is what's intended. In other words, this is meant for sanity checking only.
Back to CISCO-HSRP-MIB MIB page.
IPHost Network monitor allows you to monitor cHsrpGrpAuth on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco routers right now.