CVE-2025-20225
📋 TL;DR
An unauthenticated remote attacker can send crafted IKEv2 packets to trigger a memory leak in affected Cisco devices, causing denial of service. On IOS/IOS XE devices this causes unexpected reloads; on ASA/FTD devices it exhausts memory preventing new VPN sessions. All devices running vulnerable Cisco software with IKEv2 enabled are affected.
💻 Affected Systems
- Cisco IOS Software
- Cisco IOS XE Software
- Cisco Secure Firewall Adaptive Security Appliance (ASA) Software
- Cisco Secure Firewall Threat Defense (FTD) Software
⚠️ 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 device outage requiring manual reboot, disrupting all network services on affected devices
Likely Case
Partial memory exhaustion leading to VPN session failures and system instability
If Mitigated
Minimal impact if IKEv2 is disabled or devices are behind firewalls filtering IKEv2 traffic
🎯 Exploit Status
Requires crafting specific IKEv2 packets but no authentication needed; attacker needs network access to IKEv2 ports
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Refer to Cisco advisory for specific fixed versions per product
Vendor Advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ftd-ios-dos-DOESHWHy
Restart Required: No
Instructions:
1. Check Cisco advisory for fixed software versions. 2. Download appropriate patch from Cisco Software Center. 3. Apply patch following Cisco upgrade procedures. 4. Verify patch installation and functionality.
🔧 Temporary Workarounds
Disable IKEv2
allDisable IKEv2 feature if not required for VPN functionality
crypto ikev2 disable
Access Control Lists
allImplement ACLs to restrict IKEv2 traffic to trusted sources only
access-list IKEV2-ACL permit udp trusted-source any eq 500
access-list IKEV2-ACL permit udp trusted-source any eq 4500
access-list IKEV2-ACL deny udp any any eq 500
access-list IKEV2-ACL deny udp any any eq 4500
🧯 If You Can't Patch
- Implement strict network segmentation to isolate affected devices
- Deploy intrusion prevention systems to detect and block malicious IKEv2 packets
🔍 How to Verify
Check if Vulnerable:
Check device configuration for IKEv2: 'show running-config | include ikev2' and compare software version against Cisco advisoryCheck Version:
show versionVerify Fix Applied:
Verify patched version: 'show version' and confirm no memory leaks via 'show memory' or 'show processes memory'📡 Detection & Monitoring
Log Indicators:
- Unexpected device reloads
- Memory allocation failures
- IKEv2 session establishment failures
- High memory utilization alerts
Network Indicators:
- Unusual IKEv2 traffic patterns
- Multiple IKEv2 packets from single source
- IKEv2 packets with malformed structure
SIEM Query:
source="cisco-asa" OR source="cisco-ios" ("IKEv2" AND ("memory" OR "reload" OR "failure"))