To address the risks associated with malicious content in DNS TXT records, consider implementing the following measures:

1. **Enforce DNS Query Logging and Monitoring**: Ensure all DNS queries and responses, particularly those involving TXT records, are logged. Set up continuous monitoring to detect anomalies, such as unusual query patterns, that may indicate malicious activity.
2. **Deploy DNS Security Solutions**: Utilize DNS firewalls or other security solutions to filter malicious DNS traffic. These tools can help block suspicious DNS requests and prevent communications with malicious domains.
3. **Restrict External DNS Traffic**: Enforce strict DNS policies, limiting external DNS queries to only necessary domains. Implement DNS filtering where possible.
4. **Log and Analyze DNS Queries**: Ensure DNS queries and responses are logged for forensic analysis in case of a breach.
5. **Implement DNS Query Rate Limiting**: Enforce rate limiting for DNS queries to reduce the risk of DNS tunneling and data exfiltration. By setting a threshold for DNS requests, you can detect and prevent abuse by malicious actors.