CVE-2025-64657
📋 TL;DR
A stack-based buffer overflow vulnerability in Azure Application Gateway allows unauthorized attackers to execute arbitrary code with elevated privileges over the network. This affects organizations using vulnerable versions of Azure Application Gateway. Attackers can potentially take full control of affected gateways.
💻 Affected Systems
- Microsoft Azure Application Gateway
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of Azure Application Gateway allowing attackers to pivot to backend systems, steal sensitive data, and disrupt application availability.
Likely Case
Attackers gain administrative control of the gateway, enabling traffic interception, credential theft, and lateral movement to connected resources.
If Mitigated
With proper network segmentation and monitoring, impact is limited to the gateway instance with potential for detection and containment.
🎯 Exploit Status
Network-accessible vulnerability requiring buffer overflow exploitation skills but no authentication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Microsoft advisory for specific patched versions
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-64657
Restart Required: Yes
Instructions:
1. Review Microsoft advisory for affected versions. 2. Update Azure Application Gateway to patched version via Azure Portal or CLI. 3. Restart the gateway instance. 4. Verify update completion.
🔧 Temporary Workarounds
Network Access Restriction
allRestrict network access to Azure Application Gateway using NSGs or Azure Firewall
az network nsg rule create --resource-group <RG> --nsg-name <NSG> --name RestrictGateway --priority 100 --source-address-prefixes <AllowedIPs> --destination-address-prefixes <GatewayIP> --destination-port-ranges 443 80 --access Deny --protocol Tcp
🧯 If You Can't Patch
- Implement strict network segmentation to isolate Azure Application Gateway from critical systems
- Enable enhanced monitoring and alerting for suspicious gateway activities
🔍 How to Verify
Check if Vulnerable:
Check Azure Application Gateway version against Microsoft's advisory for affected versionsCheck Version:
az network application-gateway show --resource-group <RG> --name <GatewayName> --query "sku.tier"Verify Fix Applied:
Confirm gateway version matches patched version in Microsoft advisory and monitor for stability📡 Detection & Monitoring
Log Indicators:
- Unusual process creation on gateway
- Memory corruption errors in gateway logs
- Unexpected network connections from gateway
Network Indicators:
- Abnormal traffic patterns to/from gateway
- Exploit-like payloads in gateway traffic
SIEM Query:
source="azure-application-gateway" AND (event_type="crash" OR event_type="memory_error" OR process_name="unexpected")