Help with Regex in Azure Monitor Payload

I need help with the regex to pick the 4 values from the Custom Message which is coming from the properties in the additional information for Azure Monitor Payload.

Need to pick the ImpactedVM, Failure Code, Resource group, Recovery Vault values  from the below Custom Message.

{CustomMessage={“ImpactedVM”:”hosazr12dc02″,”FailureCode”:”UserErrorGuestAgentStatusUnavailable”,”ResourceGroup”:”rg-nga-p-eus2-sharedservices-compute-01″,”RecoveryVault”:”rsv-p-eus2-sis-backup-01″}}

I have created an event rule and when tried with the regex populating the values in the event rule but when alert is processed the unknown vales are being populated.