CVE-2023-35367 in Windows
Summary
by MITRE • 07/11/2023
Windows Routing and Remote Access Service (RRAS) Remote Code Execution Vulnerability
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 07/30/2023
The Windows Routing and Remote Access Service (RRAS) represents a critical component within Microsoft's networking infrastructure that provides essential remote access capabilities including dial-up connections, virtual private network services, and routing functions across enterprise networks. This service operates with elevated privileges and maintains deep integration with Windows authentication mechanisms, making it a prime target for sophisticated attackers seeking persistent access to corporate environments. The vulnerability in question stems from insufficient input validation within RRAS's handling of specific remote protocol messages, creating a pathway for unauthenticated remote code execution that can be exploited across the network perimeter.
The technical flaw manifests through improper validation of incoming packets within the RRAS service implementation, specifically affecting the Remote Access Service's ability to process malformed network requests. When RRAS receives crafted network traffic containing maliciously constructed data structures, the service fails to properly sanitize these inputs before processing them, leading to memory corruption vulnerabilities that can be leveraged for arbitrary code execution. This vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-125, concerning out-of-bounds read errors that can result in unpredictable behavior and potential privilege escalation. The flaw exists within the service's packet parsing logic where network protocols such as PPTP, L2TP, or other remote access protocols are processed without adequate bounds checking, allowing attackers to inject malicious payloads that execute with system-level privileges.
The operational impact of this vulnerability extends far beyond simple network disruption, as it provides attackers with a persistent foothold within enterprise environments that can be leveraged for lateral movement and data exfiltration. Once successfully exploited, the remote code execution capability allows threat actors to establish backdoors, deploy additional malware, or pivot to other systems within the network without requiring additional authentication credentials. This vulnerability particularly affects organizations running Windows Server 2012, 2016, and 2019 versions where RRAS is enabled, creating a significant risk for companies that maintain remote access capabilities or utilize legacy dial-up connections. The attack surface is further expanded when considering that many organizations maintain RRAS services for remote worker connectivity or branch office communications, making this vulnerability particularly dangerous in distributed network environments.
Mitigation strategies must address both immediate protection and long-term security posture improvements within affected organizations. The primary recommendation involves applying Microsoft's security patches as soon as they become available, specifically targeting the identified vulnerabilities in RRAS implementations. Organizations should also implement network segmentation to isolate RRAS services from critical infrastructure, utilizing firewall rules to restrict access to only necessary IP addresses and ports. Network monitoring solutions should be enhanced to detect anomalous traffic patterns that may indicate exploitation attempts, particularly focusing on unusual protocol interactions or malformed packets targeting the RRAS service ports. Additionally, implementing principle of least privilege configurations for RRAS services ensures that even if exploitation occurs, the attacker's capabilities remain limited. The ATT&CK framework categorizes this vulnerability under T1059 for command and scripting interpreter execution, and T1071 for application layer protocol usage, highlighting the need for comprehensive detection and response capabilities across multiple threat vectors. Organizations should also conduct regular security assessments to identify and disable unnecessary RRAS services, reducing the overall attack surface while maintaining essential connectivity requirements.