CVE-2023-21543
Published: 10 January 2023
Summary
CVE-2023-21543 is a high-severity Uncontrolled Resource Consumption (CWE-400) vulnerability in Microsoft Windows 10 1809. Its CVSS base score is 8.1 (High).
Operationally, ranked in the top 8.0% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
Deeper analysis
Windows Layer 2 Tunneling Protocol (L2TP) contains a remote code execution vulnerability tracked as CVE-2023-21543. The flaw affects the L2TP implementation in Windows and carries a CVSS 3.1 score of 8.1 with a network attack vector, high attack complexity, and no requirements for privileges or user interaction. Associated CWEs include CWE-400.
An unauthenticated attacker positioned on the network can send specially crafted L2TP traffic to trigger the flaw, resulting in arbitrary code execution with full impact to confidentiality, integrity, and availability on the target system.
Microsoft has published remediation guidance in its security update guide at the listed MSRC advisory URL. The EPSS score remains flat at 0.0755 with no material increase after disclosure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-25710
Vulnerability details
Windows Layer 2 Tunneling Protocol (L2TP) Remote Code Execution Vulnerability
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Limiting concurrent sessions directly prevents uncontrolled resource consumption by capping the number of active sessions per user or account.
Analysis identifies uncontrolled resource consumption indicative of denial-of-service or abuse attempts.
Contingency plan testing includes resource exhaustion scenarios to verify recovery, making it harder for attackers to sustain exploits that cause uncontrolled consumption.
Updated contingency plans include current procedures to detect, contain, and recover from resource exhaustion, limiting an attacker's ability to sustain impact from uncontrolled consumption.
Alternate site allows resumption of operations if resource exhaustion at the primary site is exploited to cause unavailability.
Alternate telecommunications services enable resumption of essential functions when primary services become unavailable due to uncontrolled resource consumption.
The team can analyze and respond to resource exhaustion incidents, reducing the impact of attacks that exploit uncontrolled consumption weaknesses.
Timely maintenance support and spare parts enable rapid recovery from failures induced by uncontrolled resource consumption, shortening the impact window of denial-of-service attacks.