CVE-2024-25583
📋 TL;DR
This vulnerability in PowerDNS Recursor allows a malicious upstream DNS server to send crafted responses that cause a denial of service. Only systems configured with recursive forwarding are affected - the default configuration is not vulnerable.
💻 Affected Systems
- PowerDNS Recursor
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete service outage of DNS resolution capabilities, disrupting all dependent services and applications.
Likely Case
Service degradation or temporary unavailability of DNS resolution for affected recursor instances.
If Mitigated
No impact if using default configuration or proper controls are implemented.
🎯 Exploit Status
Requires control over an upstream DNS server that the recursor forwards to, or ability to poison DNS responses.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.9.4 or 4.8.9
Vendor Advisory: https://doc.powerdns.com/recursor/security-advisories/powerdns-advisory-2024-02.html
Restart Required: Yes
Instructions:
1. Download and install PowerDNS Recursor 4.9.4 or 4.8.9 from official repositories. 2. Stop the recursor service. 3. Install the updated package. 4. Start the recursor service. 5. Verify the new version is running.
🔧 Temporary Workarounds
Disable recursive forwarding
allRemove or disable forward-zones and forward-zones-recurse configurations that point to untrusted upstream servers.
# Edit recursor.conf and remove/comment forward-zones* settings
# systemctl restart pdns-recursor
Restrict upstream servers
allOnly allow forwarding to trusted, controlled upstream DNS servers.
# Ensure forward-zones only point to internal/trusted DNS servers
🧯 If You Can't Patch
- Disable all recursive forwarding configurations immediately
- Implement network segmentation to isolate recursor from untrusted networks
🔍 How to Verify
Check if Vulnerable:
Check recursor.conf for forward-zones or forward-zones-recurse settings and verify if running vulnerable version.Check Version:
pdns_recursor --versionVerify Fix Applied:
Verify version is 4.9.4 or higher (or 4.8.9 for that branch) and check service is running normally.📡 Detection & Monitoring
Log Indicators:
- Unexpected service restarts
- High error rates in DNS responses
- Abnormal memory or CPU usage spikes
Network Indicators:
- DNS resolution failures
- Increased timeout responses from recursor
- Unusual traffic patterns to upstream DNS servers
SIEM Query:
source="pdns-recursor" AND (error OR restart OR crash)