CVE-2022-23613 is a vulnerability identified in neutrinolabs' xrdp, an open source implementation of the Remote Desktop Protocol (RDP) server. The flaw exists in the sesman component of xrdp, which is responsible for session management. Specifically, the vulnerability is an integer underflow (CWE-191) that leads to a heap overflow condition. This occurs when an integer value unexpectedly wraps around below zero during arithmetic operations, causing memory allocation or indexing errors. In this case, the underflow allows an attacker with local access to the sesman server to trigger a heap overflow, which can be exploited to execute arbitrary code with root privileges. The vulnerability affects versions from 0.9.17 up to but not including 0.9.18.1, where it has been patched. Notably, exploitation requires local access to the sesman server, but no authentication is needed, meaning any local user or process can potentially leverage this flaw. There are no known workarounds, so upgrading to version 0.9.18.1 or later is the only effective remediation. No public exploits have been reported in the wild to date. The vulnerability impacts the confidentiality, integrity, and availability of affected systems by enabling full root-level compromise. Given the nature of the flaw, it is a critical security risk in environments where untrusted local users or processes have access to the sesman server component of xrdp.

For European organizations, the impact of CVE-2022-23613 depends largely on the deployment of xrdp in their infrastructure. xrdp is commonly used to provide RDP access to Linux servers and desktops, often in enterprise, academic, and public sector environments. If an attacker gains local access—such as through compromised user accounts, insider threats, or other lateral movement techniques—they could exploit this vulnerability to escalate privileges to root, leading to full system compromise. This could result in data breaches, disruption of critical services, and persistent footholds within networks. Sectors with high reliance on Linux-based remote desktop services, such as financial institutions, government agencies, and technology companies, are particularly at risk. The vulnerability's requirement for local access limits remote exploitation but does not eliminate risk, especially in multi-user or shared environments. Additionally, the lack of known workarounds means organizations must prioritize patching to mitigate risk. Failure to address this vulnerability could facilitate advanced persistent threats (APTs) or insider attacks, undermining operational security and regulatory compliance within the European Union and other European countries.

1. Immediate upgrade of all xrdp installations to version 0.9.18.1 or later to apply the official patch addressing the integer underflow and heap overflow. 2. Restrict local access to the sesman server by enforcing strict access controls and limiting the number of users or processes with local privileges on systems running xrdp. 3. Implement robust monitoring and logging of local session management activities to detect unusual or unauthorized access attempts to sesman. 4. Use mandatory access control frameworks (e.g., SELinux, AppArmor) to confine the sesman process and limit the impact of potential exploitation. 5. Conduct regular audits of user accounts and permissions to minimize the risk of unauthorized local access. 6. Employ network segmentation to isolate critical systems running xrdp and reduce the attack surface. 7. Educate system administrators and users about the risks of local privilege escalation vulnerabilities and the importance of timely patching. 8. Where possible, consider alternative remote access solutions that do not expose sesman or have a smaller attack surface until patches are applied.