Overview
A critical security vulnerability, identified as CVE-2025-64657, has been discovered in Microsoft Azure Application Gateway. This vulnerability is a stack-based buffer overflow that allows an unauthorized attacker to potentially elevate privileges across the network. Given its critical severity, immediate action is highly recommended to mitigate the risk.
Technical Details
CVE-2025-64657 stems from a flaw in how Azure Application Gateway handles specific input within its request processing routines. A specially crafted request, exceeding the buffer’s capacity, can overwrite adjacent memory locations on the stack. This can be leveraged by an attacker to inject and execute arbitrary code with elevated privileges on the system hosting the Application Gateway. The exact attack vector requires careful crafting of the malicious request to ensure successful execution and privilege escalation. Further investigation is required to determine the affected components within the Azure Application Gateway service.
CVSS Analysis
This vulnerability has been assigned a CVSS score of 9.8 (CRITICAL). This high score reflects the severity and potential impact of a successful exploit. The high score is due to the following factors:
- Attack Vector: Network
- Attack Complexity: Low to Medium (depending on the specific exploit)
- Privileges Required: None (unauthorized access)
- User Interaction: None
- Scope: Changed (attacker gains control beyond the vulnerable component)
- Confidentiality Impact: High
- Integrity Impact: High
- Availability Impact: High
Possible Impact
A successful exploit of CVE-2025-64657 could lead to severe consequences, including:
- Full control of the Azure Application Gateway instance.
- Privilege escalation, potentially granting the attacker access to other resources within the Azure environment.
- Data breaches and exfiltration of sensitive information.
- Denial-of-service (DoS) attacks, disrupting critical services.
- Compromise of the entire network if lateral movement is possible.
Mitigation and Patch Steps
Microsoft has released a security update to address this vulnerability. The following steps are recommended to mitigate the risk:
- Immediately apply the latest security update released by Microsoft for Azure Application Gateway. Refer to the Microsoft Security Response Center (MSRC) advisory for detailed instructions.
- Verify the update’s successful installation by checking the Application Gateway version.
- Monitor your Azure environment for any suspicious activity or unauthorized access attempts.
- Review network segmentation to limit the potential impact of a compromised Application Gateway instance.
- Implement or strengthen intrusion detection and prevention systems (IDS/IPS) to identify and block malicious traffic.
